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| Meta Title | Compliance with face mask use during the COVID-19 pandemic: a community observational study in Singapore - PMC |
| Meta Description | Widespread mask use is an important intervention for control of the coronavirus disease 2019 pandemic. However, data on the factors affecting mask use are lacking. In this observational study, we evaluated the proportion of and factors influencing ... |
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| Boilerpipe Text | Abstract
Introduction:
Widespread mask use is an important intervention for control of the coronavirus disease 2019 pandemic. However, data on the factors affecting mask use are lacking. In this observational study, we evaluated the proportion of and factors influencing face mask use and related hygiene practices.
Methods:
We observed randomly selected members from the public in 367 venues across Singapore, and recorded the proportion of individuals with full compliance with mask use and mask hygiene (hand hygiene before and after touching the mask or face). Logistic regression analyses were used to determine variables associated with mask and hand hygiene compliance.
Results:
We made 3,821 observations — 2,149 (56.2%) females, 3,569 (93.4%) adults (≥21 years), 212 (5.5%) children (6–20 years) and 40 (1.0%) children (2–5 years). The overall full compliance rate (correct mask use), poor compliance rate (incorrect mask use) and absent mask use were 84.5%, 12.9% and 2.6%, respectively. The factors — male gender, fabric mask usage and crowded indoor venues — were associated with lower mask compliance. Face or mask touching behaviour was observed in 10.7% and 13.7% of individuals observed, respectively. Only one individual performed hand hygiene before and after touching the mask.
Conclusion:
The rate of mask compliance was high, probably due to legislation mandating mask usage. However, specific factors and crowded indoor venues associated with lower mask compliance were identified. We also noted an issue with the absence of hand hygiene before and after face or mask touching. These issues may benefit from targeted public health messaging.
Keywords:
COVID-19, face mask, mask usage, public health, SARS-CoV-2
INTRODUCTION
The coronavirus disease 2019 (COVID-19) pandemic has expanded exponentially across the globe in less than a year and has impacted healthcare systems, the global economy, societal norms and our daily lives irrevocably. One visible impact is that the use of face masks has been thrust into central focus, becoming a polarising issue that has been divisive, even along political lines.[
1
]
There is accumulating data that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spreads via airborne or aerosol transmission.[
2
,
3
] Consequently, most advisory bodies, including the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) have formally recommended widespread usage of surgical or face masks in the community to limit transmission of COVID-19 via droplets and respiratory aerosols.[
4
,
5
] As SARS-CoV-2 transmission by asymptomatic or pre-symptomatic individuals has been reported, a universal face mask policy has an important role to play in a multi-pronged approach for outbreak control.[
6
,
7
]
Modelling studies have demonstrated that widespread or universal use of face masks in the community has a significant impact on curtailing transmission, with a consequent reduction in mortality rates.[
8
,
9
] Several epidemiologic investigations have also reported the use of face masks being associated with preventing transmission in situations whereby large outbreaks may have otherwise occurred.[
10
,
11
,
12
] Even if face mask use does not eliminate infection risk, it may lower the viral inoculum that an individual is exposed to, resulting in a clinically milder infection.[
13
,
14
]
However, beyond simply ensuring high rates of community mask use, it is equally important to ensure that proper face mask usage and hygiene is followed. Improper use of face masks (e.g. not adequately covering mouth and nose, and not observing hand hygiene) may compromise their protective effect. Community observational studies have evaluated the general public’s proficiency in N95 respirator usage[
15
]; however, there is scant data on compliance to proper face mask usage, which is crucial data required especially during the COVID-19 pandemic.
In this community observational study, we evaluated the proportion of face mask usage, the extent of correct face mask usage and face mask-related hygiene practices among the general public in Singapore.
METHODS
Study design
This observational study was conducted from 29 July 2020 to 18 August 2020. During this period, it was mandatory to wear a face mask in all public areas in Singapore (since 15 April 2020), and individuals were subject to a monetary fine of SGD 300 (approximately USD 220) if they were caught not complying with the law. Face shields were allowed as an alternative to face masks in specific situations only such as for children (<12 years) who have difficulty wearing a mask for a prolonged period and individuals with health conditions who may have difficulty breathing after prolonged mask use. Children below 2 years of age and children with special needs were exempted from wearing face masks.[
16
]
Ten trained study team members were deployed in public areas to observe members of the public anonymously from a distance. The study team members were trained by the principal investigator who designed the study protocol, using clear, written instructions and illustrative examples pertaining to the criteria required for qualification as full compliance to mask wearing. The individuals surveyed were not informed that they were being observed, and no individually identifiable data were collected. The list of locations surveyed was spread across different neighbourhoods in Singapore by randomly selecting 38 mass rapid transit (MRT) stations (the public train system with a dense network of stations serving the entire island) and centring sampling venues around these stations.
Data collection
Study team members collected data on mask usage using a standardised data collection form. Individuals were observed for a minimum of 5 minutes. The following parameters were recorded: (a) activity that the individual was doing; (b) the type of mask used; (c) whether the mask was used correctly; (d) the method of securing the mask (ear loops, use of loop extender or tied around the head); (e) whether the individual touched the mask or face; and (f) whether hand hygiene was performed before and after touching the mask or face. Demographic data on gender and estimated age (infant: <2 years, child: 2–5 years, child: 6–20 years and adult: ≥21 years), as well as location data (type of venue and whether venue was crowded) were also collected.
‘Full compliance’ was defined as use of any one of the following type of face masks — fabric mask, surgical mask, face shield, a combination of face mask and face shield, or N95 mask, with the mask or shield fully covering the individual’s mouth and nose, upper boundary moulded over the nose with an appropriate fit and lower boundary below the chin. ‘Poor compliance’ was defined as wearing a mask incorrectly (e.g. with either the mouth or nose exposed, the mask around the chin or neck, the upper or lower boundary is not fitted properly) or using an inappropriate mask (e.g. mask with valve). ‘No mask’ was defined as not wearing any facial covering at all (either face mask or face shield). In accordance with Singapore law, exceptions to mask usage are allowed in specific circumstances of eating, drinking, exercising or driving alone or with family members in the car; these were recorded as instances of ‘allowable non-compliance’ if individuals were wearing a mask inappropriately or not wearing a mask during these circumstances. Individuals were not counted as an instance of non-compliance if they did not put on their mask immediately after eating or drinking. Two main methods were used to assess that a meal was completed: (a) there was no unfinished food or drink left on the table; and (b) there was no further consumption of food or drink for a five-minute observation duration. If the individual was not wearing a face mask or face shield after completing their meal for some time, it was recorded as an instance of non-compliance. Detailed notes on the exact activity and exemption criteria were recorded for arbitration by another member of the study team in ambiguous circumstances. A ‘crowded venue’ was defined as an environment where safe distancing of one metre between individuals is not possible due to the number of people at the venue.
Statistical methods
All variables analysed were categorical and compared using χ
2
test. Univariate and multivariate binary logistic regression analyses were used to determine odds ratios and 95% confidence intervals for variables associated with full mask compliance by comparing full mask compliance against incorrect or absent mask use. Hosmer–Lemeshow test was used to assess the goodness-of-fit of the multivariate model.
P
values <0.05 were considered significant, and all tests were two-tailed. Analyses were performed using Stata Statistical Software: Release 13 (StataCorp LP, College Station, TX, USA).
Ethical approval
This study was approved by the institutional review board (National Healthcare Group Domain Specific Review Board; reference number: 2020/00951) with a waiver of informed consent since there was no direct contact with individuals observed, observations were carried out only in public spaces, and no individually identifiable data were collected.
RESULTS
A total of 3,851 observations were recorded from 367 unique locations in 38 neighbourhoods [
Supplementary Figure 1
(118.3KB, tif)
, Appendix]. The location types varied with a mix of food and beverage (F&B) establishments (both indoor and outdoor), healthcare facilities, public transport, retail and services and open public spaces; with open public spaces being the most common category (1,497 observations or 38.9%) [
Supplementary Table 1
, Appendix]. After excluding children aged <2 years (29 observations) and children with special needs (one observation) for whom mask usage is not mandated, there were 3,821 observations that were analysed. Of these 3,821 observed individuals, 2,149 (56.2%) were female, 3,569 (93.4%) were adults (≥21 years), 212 (5.5%) were children estimated to be 6–20 years old and 40 (1.0%) were children estimated to be 2–5 years old. As no individual identifiers were collected, it is not known whether any individual was observed more than once at different locations or time points.
The overall proportion of full compliance with mask usage in the study was 79.7%, while that for poor compliance with mask usage and no usage of mask was 14.0% and 6.3%, respectively [
Table 1
]. After correcting for instances of ‘allowable non-compliance’, the overall proportions of full compliance, poor compliance and no mask usage were 84.5%, 12.9% and 2.6%, respectively. Pitfalls in mask wearing included covering the mouth and nose but having large gaps above or below the mask (235/464, 50.7% of poor compliance observations), not covering the nose (
n
= 140, 30.2%), wearing the mask around the chin (
n
= 67, 14.4%), hanging the mask on the neck (
n
= 7, 1.5%) or dangling the mask on one ear (
n
= 9, 1.9%).
Table 1.
Overall compliance to mask use by different age groups
a
.
Variable
n
(%)
Total
Full compliance
b
Poor compliance
c
No mask
d
Before excluding allowable reasons for mask non-compliance
e
Adult (≥21 years)
2,848 (79.8)
505 (14.1)
217 (6.1)
3,569
Child (6–20 years)
177 (83.5)
23 (10.8)
11 (5.2)
212
Child (2–5 years)
22 (55)
6 (15)
12 (30)
40
Total
3,047 (79.7)
534 (14.0)
240 (6.3)
3,821
After excluding allowable reasons for mask non-compliance
e
Adult (≥21 years)
2,848 (84.5)
440 (13.0)
85 (2.5)
3,372
Child (6–20 years)
177 (88.1)
20 (10.0)
3 (1.5)
201
Child (2–5 years)
22 (66.7)
4 (12.1)
7 (21.2)
33
Total
3,047 (84.5)
464 (12.9)
95 (2.6)
3,606
a
Age groups refers to estimated age.
b
‘Full compliance’ with mask usage was defined as using any one of the following type of face mask: fabric mask, surgical mask, face shield, a combination of face mask and face shield, or N95 mask, with the mask or shield fully covering the individual’s mouth and nose, upper boundary moulded over the nose with an appropriate fit and lower boundary below the chin.
c
‘Poor compliance’ with mask usage was defined as wearing a mask incorrectly (e.g. with either the mouth or nose exposed, the mask around the chin or neck, the upper or lower boundary is not fitted properly) or using an inappropriate mask (e.g. mask with valve).
d
‘No mask’ was defined as not wearing any facial covering at all.
e
According to the Singapore law, individuals are allowed to remove their mask for the following activities: eating or drinking, exercising or driving alone/with family members in the car
Male gender was associated with incorrect or absent mask use (adjusted odds ratio [aOR] 0.69, 95% confidence interval [CI] 0.56–0.85) [
Table 2
]. Use of a surgical mask was associated with improved compliance (aOR 1.99, 95% CI 1.62–2.44) as compared to the use of a fabric mask. Full mask compliance was less frequently observed in spaces that were crowded (OR 0.77, 95% CI 0.64–0.93 in univariate analysis). A detailed analysis of venue categories found that mask compliance was lower in indoor F&B establishments, healthcare facilities and retail and service venues compared to open public spaces, with a corrected compliance rate of 88.3% in open spaces but falling to 70.0% in indoor F&B establishments [
Figure 1
]. Instances of pitfalls in mask wearing in F&B venues occurred while queueing, ordering food, waiting for food, talking, serving food or cleaning tables.
Table 2.
Binary logistic regression analysis of factors associated with poor mask compliance or no mask usage.
Variable
n
(%)
Univariate analysis
Multivariate analysis
Full compliance (
n
=3,047)
Poor compliance or no mask use (
n
=559)
OR (95% CI) for full compliance
P
OR ratio (95% CI) for full compliance
P
Male gender
1,269 (41.7)
289 (51.7)
0.67 (0.56–0.80)
<0.0001
0.69 (0.56–0.85)
<0.0001
Age group
0.007
Adult (≥21 years)
2,848 (93.5)
524 (93.7)
Ref
Ref
Ref
Ref
Child (6–20 years)
177 (5.8)
24 (4.3)
1.36 (0.88–2.10)
0.17
1.52 (0.93–2.49)
0.09
Child (2–5 years)
22 (0.7)
11 (2.0)
0.37 (0.18–0.76)
0.007
0.72 (0.24–2.16)
0.56
Type of mask
<0.0001
Fabric mask
1,122 (36.9)
246 (53.0)
Ref
Ref
Ref
Ref
Surgical mask
1,907 (62.6)
217 (46.8)
1.93 (1.58–2.35)
<0.0001
1.99 (1.62–2.44)
<0.001
Face shield
0
1 (0.22)
NA
NA
NA
NA
N95 respirator
4 (0.13)
0
NA
NA
NA
NA
Both mask and shield
12 (0.39)
0
NA
NA
NA
NA
Securing method
0.42
Ear loop
2,857 (94.0)
444 (95.5)
Ref
Ref
Ref
Ref
Tied around head
45 (1.5)
6 (1.3)
1.17 (0.49–2.75)
0.73
1.00 (0.42–2.39)
>0.99
Loop extender
137 (4.5)
15 (3.2)
1.42 (0.83–2.44)
0.21
1.25 (0.72–2.19)
0.43
Crowded venue
a
1,031 (33.8)
223 (39.9)
0.77 (0.64–0.93)
0.006
0.85 (0.67–1.06)
0.15
Type of location
<0.0001
Open public space
1,258 (41.3)
166 (29.7)
Ref
Ref
Ref
Ref
F&B (indoor)
266 (8.7)
114 (20.4)
0.31 (0.23–0.40)
<0.0001
0.41 (0.29–0.59)
<0.001
F&B (outdoor)
134 (4.4)
49 (8.8)
0.36 (0.25–0.52)
<0.0001
0.66 (0.40–1.10)
0.11
Healthcare facility
180 (5.9)
41 (7.3)
0.58 (0.40–0.84)
0.004
0.61 (0.39–0.94)
0.03
Transportation
672 (22.1)
89 (15.9)
1.00 (0.76–1.31)
0.98
0.85 (0.60–1.18)
0.33
Retail and services
537 (17.6)
100 (17.9)
0.71 (0.54–0.93)
0.012
0.57 (0.42–0.79)
0.001
Type of activity
<0.0001
Standing or sitting idly
324 (10.8)
91 (16.3)
Ref
Ref
Ref
Ref
Customer service
206 (6.8)
16 (2.9)
3.62 (2.07–6.33)
<0.0001
3.62 (1.95–6.75)
<0.001
Using electronic device
334 (11.1)
49 (8.8)
1.91 (1.31–2.80)
<0.0001
2.89 (1.80–4.62)
<0.001
Preparing food or beverage
48 (1.6)
10 (1.8)
1.35 (0.66–2.77)
0.42
1.63 (0.71–3.72)
0.25
Shopping
412 (13.4)
64 (11.5)
1.81 (1.27–2.57)
0.001
2.38 (1.55–3.64)
<0.001
Smoking
0
17 (3.0)
NA
NA
NA
NA
Using transportation service
229 (7.6)
23 (4.1)
2.80 (1.72–4.55)
<0.0001
2.19 (1.25–3.82)
0.006
Talking
617 (20.5)
158 (28.3)
1.10 (0.82–1.47)
0.53
1.31 (0.93–1.85)
0.12
Walking
843 (28.0)
131 (23.4)
1.81 (1.34–2.43)
<0.0001
1.55 (1.10–2.19)
0.01
Exempted activity
b
34 (1.1)
0
NA
NA
NA
NA
P
values were obtained using
χ
2
test for comparison across categorical variables, and binary logistic regression was used to obtain the individual OR of each variable. Hosmer–Lemeshow test was used for goodness-of-fit of multivariable model (
P
= 0.791).
a
Crowded venue was defined as an environment where safe distancing of 1 m between individuals is not possible due to the number of people in the venue.
b
Exempted activity includes eating, drinking, exercising or driving, whereby mask use is neither mandated or practical. CI: confidence interval, F&B: food and beverage establishment, NA: not applicable, OR: odds ratio, Ref: reference variable
Figure 1.
Graph shows the proportion of individuals observed with full mask compliance (excluding instances of allowable non-compliance) by venue type. F&B: food and beverage establishment (e.g. restaurant, hawker centre, food court).
An analysis of face or mask touching behaviour showed that a large proportion of individuals touched their mask (10.7%) or face (13.5%) during the observations [
Table 3
]. The most common area of the face touched was the head (35.6%), followed by the mouth (21.4%) [
Figure 2
]. Of significant concern is the small number of individuals who performed hand hygiene before (
n
= 2) and after (
n
= 3) touching their mask or face [
Table 3
]. Only one individual performed hand hygiene both before and after as per the recommended infection control precautions.
Table 3.
Frequency of mask or face touching behaviour and hand hygiene by age.
Age group
a
n
(%)
Touched mask
Touched face
Hand hygiene before
b
Hand hygiene after
b
Adult (≥21 years)
377 (10.6)
466 (13.1)
2 (0.28)
3 (0.42)
Child (6–20 years)
30 (14.2)
38 (17.9)
0
0
Child (2–5 years)
3 (7.5)
10 (25)
0
0
Total
410 (10.7)
514 (13.5)
2 (0.25)
3 (0.38)
a
Age group refers to estimated age.
b
Percentage is expressed using the denominator of the number of individuals who touched either their mask or face.
Figure 2.
Graph shows the frequency of different areas of the face touched during face-touching observations. Percentages are expressed using the denominator of the number of individuals who touched their face, with some observed to have touched more than one area. ‘Face’ refers to the areas of the face other than the mouth, nose, ears or eyes.
Being fully compliant with mask usage was associated with a lower rate of face or mask touching behaviour [
Tables 3
and
4
]. Children were also more likely to touch their mask or face. The use of a surgical mask compared to a fabric mask was significantly associated with a lower rate of touching one’s face or mask (OR 0.84, 95% CI 0.71–0.99). No significant differences were identified between different methods of wearing a face mask (e.g. ear loops, tying behind one’s head or use of a dedicated loop extender). Being in a crowded area was associated with increased face or mask touching behaviour, similar to the effect on lowered mask compliance.
Table 4.
Factors associated with mask or face touching behaviour.
Variable
n
(%)
Odds ratio (95% CI)
P
Mask or face touching (
n
=789)
No mask or face touching (
n
=3,032)
Male gender
337 (42.7)
1335 (44.0)
0.95 (0.81–1.11)
0.51
Age group
a
0.001
Adult (≥21 years)
714 (90.5)
2855 (94.2)
Ref
Ref
Child (6–20 years)
62 (7.9)
150 (5.0)
1.65 (1.22–2.25)
0.001
Child (2–5 years)
13 (1.7)
27 (0.9)
1.93 (0.99–3.75)
0.054
Type of mask
0.07
Fabric mask
296 (42.8)
1106 (38.3)
Ref
Ref
Surgical mask
396 (57.2)
1763 (61.1)
0.84 (0.71–0.99)
0.04
Face shield
0
2 (0.07)
NA
NA
N95 respirator
0
4 (0.14)
NA
NA
Both mask and shield
0
12 (0.42)
NA
NA
Securing method
0.52
Ear loop
660 (94.7)
2704 (93.9)
Ref
Ref
Tied around head
7 (1.0)
45 (1.6)
0.64 (0.29–1.42)
0.27
Loop extender
30 (4.3)
130 (4.5)
0.95 (0.63–1.42)
0.79
Full mask compliance
506 (64.1)
2541 (83.8)
0.35 (0.29–0.41)
<0.0001
Crowded venue
b
311 (39.4)
1044 (34.4)
1.24 (1.05–1.46)
0.009
P
values were obtained using
χ
2
test for comparison across categorical variables, and binary logistic regression was used to obtain the individual odds ratio of each variable.
a
Age group refers to estimated age.
b
Crowded venue was defined as an environment where safe distancing of 1 m between individuals is not possible due to the number of people in the venue. CI: confidence interval, NA: not applicable, Ref: reference variable
DISCUSSION
This study assessed the compliance rate and appropriate use of face masks by the general public across a broad range of public venues. The overall rate of mask compliance was high at 84.5%, which is higher than reported rates in other countries such as the United States, the United Kingdom and Australia.[
17
] This is likely largely due to strict legislation mandating mask usage in Singapore. Other contributing factors could include active enforcement by safe distancing ambassadors (designated public health officers who patrol public spaces to ensure compliance with public health measures) and high level of public trust in the Singapore government. Nonetheless, we identified several problem areas in mask usage and personal hygiene.
First, we identified key demographic groups that may benefit from improved targeted public health messaging (men for appropriate mask usage and children for face and mask touching behaviour). This finding of lower mask-wearing compliance rates among men is similar to the findings of Haischer and colleagues in a similar community mask audit study conducted in the United States.[
18
]
Second, we identified several venues (indoor F&B establishments, healthcare facilities and retail and services) where mask usage is comparably lower, and these places will benefit from improved surveillance and/or reminders to improve compliance. The finding that more crowded areas are associated with decreased mask compliance and increased face and mask touching behaviour is concerning and unexpected, given that the transmission risk is expected to be the greatest in crowded areas.[
19
] We hypothesise that ventilation may be comparably poorer in crowded areas, resulting in more sweating and discomfort for mask users, and hence, higher rates of mask or face touching for mask adjustment, leading to poor compliance. An alternative explanation could be that in crowded indoor areas, people feel like they are less likely to be caught or policed for non-compliance, resulting in more lax behaviour. Systemic interventions should be considered to ensure that such situations are minimised, for example optimising ventilation and air-flow, imposing venue capacity limitations or increasing surveillance.[
19
]
Third, the finding of almost zero hand hygiene practised before and after face or mask touching is of concern and should be emphasised in future public health messaging. Avoidance of touching of one’s eyes, mouth and nose is advised to prevent the inoculation of SARS-CoV-2 by touch after contact with contaminated surfaces,[
20
] and thus hand hygiene before and after face or mask touching is an important instruction that should be disseminated. Theoretical concern has also been raised that the use of face masks would be associated with an increased incidence of users touching their face (e.g. to adjust the mask or to scratch their nose or mouth) as a result of the discomfort associated with mask wearing, resulting in a counterproductive effect. In contrast, a large international cross-sectional study by Chen
et al.
, which compared the observations of 2,887 individuals during the pandemic with 4,699 individuals before the pandemic, showed that mask usage was associated with reduced face-touching behaviour.[
21
] While we had no pre-pandemic data to compare the incidence of face-touching behaviour, in our study, we found that individuals who were fully compliant with mask usage had less face-touching behaviour compared to those who had poor compliance or did not use a mask, suggesting that face mask use was associated with reduced face-touching behaviour, though this association could be explained by an overall more conscientious attitude towards hygiene rather than direct causation. Of note, face-touching rates in our study were much higher than those reported by Chen
et al
. and comparable to their reported pre-pandemic rates (4.1%, 11.2% and 11.4% in China, South Korea and Europe, respectively).
The evidence for the optimal mask for use in healthcare settings remains inconclusive, with debate over whether a particulate respirator (e.g. filtering face piece [FFP]-2 or N95 respirator) is necessary in all healthcare settings.[
2
,
22
] However, it is clear that widespread adoption of particulate respirators for the general public is not recommended, given the issues with resource limitations, requirement for fit testing and poor mask-wearing proficiency.[
15
] Public health messaging that N95 respirators are not required for general use was consistent, and we note that only four observations of N95 mask use were made.
Non-traditional or alternative materials for masks (such as cotton, silk or linen) have been evaluated in
in vitro
studies of filtration efficacy, and while they may be less effective than conventional surgical masks,[
23
] they nonetheless proffer some degree of protection and may provide advantages in terms of comfort and availability. However, in this study, we observed that the use of fabric masks, as compared to surgical masks, is associated with poorer mask compliance and increased face or mask touching behaviour, and this is concerning and merits further evaluation. One possible explanation is that there were unmeasured confounding factors, and the demographics of fabric mask users could be different from that of surgical mask users (e.g. they could be less careful or informed, and hence paid less attention to infection control precautions).
Our study has several limitations. First, as it was only done in a single country, the findings may not necessarily be applicable to other settings, especially in countries where mask policy is not backed by law, or where other cultural or political influences affect the decision to use a mask. Second, we did not collect individually identifiable information or conduct detailed individual surveys, and hence could not further narrow down the demographic factors associated with mask compliance or evaluate the general public’s knowledge and attitudes towards mask use. For that same reason, the categorised age groups were only an estimate based on the child’s appearance and there may have been mis-classification in some instances. Furthermore, observations were conducted during daytime office hours only; hence, we did not explore the impact of time of day on mask-wearing behaviour. Third, while effort was made to ensure a good distribution of locations across the country, there was no systematic selection of sampling venues, and venues were instead selected on a best-effort basis by study team members based on proximity to the allocated MRT station. Nonetheless, the amount of bias this may have introduced should be minimal. Lastly, we did not conduct any statistical testing or external validation to assess if there was significant inter-observer variability among study team members; however, we assess that the amount of bias introduced by this factor to be very minimal.
In conclusion, compliance to mask usage was high during the COVID-19 pandemic in Singapore. However, we identified key problem areas to optimise future public health messaging, including high-risk venues where mask usage should be reinforced and the importance of hand hygiene before and after touching of one’s mask or face. Future studies can examine behavioural interventions at crowded areas to improve compliance. Similar community studies should be conducted in other settings to better inform and tailor public health policies.
Conflicts of interest
Vasoo S is a member of the SMJ Editorial Board and was not involved in the publication decision of this article. The abovementioned funders played no role in the design and conduct of the study; the collection, management, analysis and interpretation of the data; the preparation, review or approval of the manuscript, and the decision to submit the manuscript for publication.
Supplemental digital content
Appendix at
https://links.lww.com/SMJ/xx
Supplementary Figure. 1
Spread of locations surveyed outlined on the Singapore map.
APPENDIX
Supplementary Table 1.
Breakdown of location types surveyed.
Type of location
Number of observations
Percentage
F&B (Indoor)
493
12.8
F&B (Outdoor)
222
5.8
Healthcare Facilities
225
5.8
Public Transport
771
20.0
Public Spaces
1497
38.9
Retail & Services
643
16.7
Total
3851
100
F&B: food & beverage establishment (e.g. restaurant, hawker centre, food court)
Funding Statement
This study was funded by the National Health Group–National Centre for Infectious Diseases COVID-19 Centre Grant (COVID19 CG0002). Ng OT is supported by the National Medical Research Council (NMRC) Clinician Scientist Award (MOH-000276). Marimuthu K is supported by the NMRC Clinician Scientist-Individual Research Grant (CIRG18Nov-0034).
REFERENCES
1.
Flaskerud JH. Masks, politics, culture and health. Issues Ment Health Nurs. 2020;41:846–9. doi: 10.1080/01612840.2020.1779883.
[
DOI
] [
PubMed
] [
Google Scholar
]
2.
Ong SWX, Coleman KK, Chia PY, Thoon KC, Pada S, Venkatachalam I, et al. Transmission modes of severe acute respiratory syndrome coronavirus 2 and implications on infection control: A review. Singapore Med J. 2022;63:61–7. doi: 10.11622/smedj.2020114.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
3.
Sommerstein R, Fux CA, Vuichard-Gysin D, Abbas M, Marschall J, Balmelli C, et al. Risk of SARS-CoV-2 transmission by aerosols, the rational use of masks, and protection of healthcare workers from COVID-19. Antimicrob Resist Infect Control. 2020;9:100. doi: 10.1186/s13756-020-00763-0.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
4.
Advice on the use of masks in the context of COVID-19: World Health Organization. 2020. [Last accessed on 2020 Aug 18]. [Updated 2020 Jun 05] Available from:
https://apps.who.int/iris/bitstream/handle/10665/332293/WHO-2019-nCov-IPC_Masks-2020.4-eng.pdf
.
5.
Considerations for Wearing Masks: Centers for Disease Control and Prevention. 2020. [Last accessed on 2020 Aug 18]. [Updated 2020 Aug 07] Available from:
https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html
.
6.
Wei WE, Li Z, Chiew CJ, Yong SE, Toh MP, Lee VJ. Presymptomatic transmission of SARS-CoV-2-Singapore, January 23-March 16, 2020. MMWR Morb Mortal Wkly Rep. 2020;69:411–5. doi: 10.15585/mmwr.mm6914e1.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
7.
Furukawa NW, Brooks JT, Sobel J. Evidence supporting transmission of severe acute respiratory syndrome coronavirus 2 while presymptomatic or asymptomatic. Emerg Infect Dis. 2020;26:e201595. doi: 10.3201/eid2607.201595.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
8.
Eikenberry SE, Mancuso M, Iboi E, Phan T, Eikenberry K, Kuang Y, et al. To mask or not to mask: Modeling the potential for face mask use by the general public to curtail the COVID-19 pandemic. Infect Dis Model. 2020;5:293–308. doi: 10.1016/j.idm.2020.04.001.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
9.
Worby CJ, Chang HH. Face mask use in the general population and optimal resource allocation during the COVID-19 pandemic. Nat Commun. 2020;11:4049. doi: 10.1038/s41467-020-17922-x.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
10.
Schwartz KL, Murti M, Finkelstein M, Leis JA, Fitzgerald-Husek A, Bourns L, et al. Lack of COVID-19 transmission on an international flight. CMAJ. 2020;192:E410. doi: 10.1503/cmaj.75015.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
11.
Hendrix MJ, Walde C, Findley K, Trotman R. Absence of apparent transmission of SARS-CoV-2 from two stylists after exposure at a hair salon with a Universal Face Covering Policy —Springfield, Missouri, May 2020. MMWR Morb Mortal Wkly Rep. 2020;69:930–2. doi: 10.15585/mmwr.mm6928e2.
[
DOI
] [
PubMed
] [
Google Scholar
]
12.
Cheng VC, Wong SC, Chuang VW, So SY, Chen JH, Sridhar S, et al. The role of community-wide wearing of face mask for control of coronavirus disease 2019 (COVID-19) epidemic due to SARS-CoV-2. J Infect. 2020;81:107–14. doi: 10.1016/j.jinf.2020.04.024.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
13.
Guallar MP, Meirino R, Donat-Vargas C, Corral O, Jouve N, Soriano V. Inoculum at the time of SARS-CoV-2 exposure and risk of disease severity. Int J Infect Dis. 2020;97:290–2. doi: 10.1016/j.ijid.2020.06.035.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
14.
Gandhi M, Beyrer C, Goosby E. Masks do more than protect others during covid-19: Reducing the inoculum of SARS-CoV-2 to protect the wearer. J Gen Intern Med. 2020;35:3063–6. doi: 10.1007/s11606-020-06067-8.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
15.
Yeung W, Ng K, Fong JMN, Sng J, Tai BC, Chia SE. Assessment of proficiency of n95 mask donning among the general public in Singapore. JAMA Netw Open. 2020;3:e209670. doi: 10.1001/jamanetworkopen.2020.9670.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
16.
Guidance for use of masks and face shields: Ministry of Health. Singapore: 2020. [Last accessed on 2020 Aug 18]. Available from:
https://www.moh.gov.sg/news-highlights/details/guidance-for-use-of-masks-and-face-shields
.
[
Google Scholar
]
17.
MacIntyre CR, Nguyen PY, Chughtai AA, Trent M, Gerber B, Steinhofel K, et al. Mask use, risk-mitigation behaviours and pandemic fatigue during the COVID-19 pandemic in five cities in Australia, the UK and USA: A cross-sectional survey. Int J Infect Dis. 2021;106:199–207. doi: 10.1016/j.ijid.2021.03.056.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
18.
Haischer MH, Beilfuss R, Hart MR, Opielinski L, Wrucke D, Zirgaitis G, et al. Who is wearing a mask?Gender-, age-, and location-related differences during the COVID-19 pandemic. PLoS One. 2020;15:e0240785. doi: 10.1371/journal.pone.0240785.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
19.
Morawska L, Tang JW, Bahnfleth W, Bluyssen PM, Boerstra A, Buonanno G, et al. How can airborne transmission of COVID-19 indoors be minimised? Environ Int. 2020;142:105832. doi: 10.1016/j.envint.2020.105832.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
20.
Coronavirus disease (COVID-19) advice for the public: World Health Organization. 2020. [Last accessed on 2020 Aug 18]. Available from:
https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public
.
21.
Chen YJ, Qin G, Chen J, Xu JL, Feng DY, Wu XY, et al. Comparison of face-touching behaviors before and during the coronavirus disease 2019 pandemic. JAMA Netw Open. 2020;3:e2016924. doi: 10.1001/jamanetworkopen.2020.16924.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
22.
Conly J, Seto WH, Pittet D, Holmes A, Chu M, Hunter PR, et al. Use of medical face masks versus particulate respirators as a component of personal protective equipment for health care workers in the context of the COVID-19 pandemic. Antimicrob Resist Infect Control. 2020;9:126. doi: 10.1186/s13756-020-00779-6.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
23.
Wilson AM, Abney SE, King MF, Weir MH, Lopez-Garcia M, Sexton JD, et al. COVID-19 and use of non-traditional masks: How do various materials compare in reducing the risk of infection for mask wearers? J Hosp Infect. 2020;105:640–2. doi: 10.1016/j.jhin.2020.05.036.
[
DOI
] [
PMC free article
] [
PubMed
] [
Google Scholar
]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Supplementary Figure. 1
Spread of locations surveyed outlined on the Singapore map. |
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# Compliance with face mask use during the COVID-19 pandemic: a community observational study in Singapore
[Sean Wei Xiang Ong](https://pubmed.ncbi.nlm.nih.gov/?term="Ong%20SWX"[Author])
### Sean Wei Xiang Ong, MBBS
1National Centre for Infectious Diseases, Singapore
2Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore
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1National Centre for Infectious Diseases, Singapore
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1National Centre for Infectious Diseases, Singapore
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1National Centre for Infectious Diseases, Singapore
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1National Centre for Infectious Diseases, Singapore
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1National Centre for Infectious Diseases, Singapore
2Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore
3Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
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### Yee-Sin Leo, MBBS, MPH
1National Centre for Infectious Diseases, Singapore
2Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore
3Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
4Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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3Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
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### Kalisvar Marimuthu, MBBS
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1,2,4,5,✉
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1National Centre for Infectious Diseases, Singapore
2Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore
3Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
4Yong Loo Lin School of Medicine, National University of Singapore, Singapore
5Infection Prevention and Control Office, Woodlands Health Campus, Singapore
✉
**Correspondence:** Dr. Kalisvar Marimuthu, Senior Consultant, National Centre for Infectious Diseases, 16 Jalan Tan Tock Seng, 308442, Singapore. E-mail: kalisvar\_marimuthu@ncid.sg
Received 2021 Jan 6; Accepted 2022 Feb 5; Collection date 2024 Dec.
Copyright: © 2023 Singapore Medical Journal
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PMCID: PMC11698284 PMID: [37171431](https://pubmed.ncbi.nlm.nih.gov/37171431/)
See commentary "[COVID-19 vaccination strategy in Singapore: perspectives and lessons from primary care](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698280/)" on page 681.
## Abstract
### Introduction:
Widespread mask use is an important intervention for control of the coronavirus disease 2019 pandemic. However, data on the factors affecting mask use are lacking. In this observational study, we evaluated the proportion of and factors influencing face mask use and related hygiene practices.
### Methods:
We observed randomly selected members from the public in 367 venues across Singapore, and recorded the proportion of individuals with full compliance with mask use and mask hygiene (hand hygiene before and after touching the mask or face). Logistic regression analyses were used to determine variables associated with mask and hand hygiene compliance.
### Results:
We made 3,821 observations — 2,149 (56.2%) females, 3,569 (93.4%) adults (≥21 years), 212 (5.5%) children (6–20 years) and 40 (1.0%) children (2–5 years). The overall full compliance rate (correct mask use), poor compliance rate (incorrect mask use) and absent mask use were 84.5%, 12.9% and 2.6%, respectively. The factors — male gender, fabric mask usage and crowded indoor venues — were associated with lower mask compliance. Face or mask touching behaviour was observed in 10.7% and 13.7% of individuals observed, respectively. Only one individual performed hand hygiene before and after touching the mask.
### Conclusion:
The rate of mask compliance was high, probably due to legislation mandating mask usage. However, specific factors and crowded indoor venues associated with lower mask compliance were identified. We also noted an issue with the absence of hand hygiene before and after face or mask touching. These issues may benefit from targeted public health messaging.
**Keywords:** COVID-19, face mask, mask usage, public health, SARS-CoV-2
## INTRODUCTION
The coronavirus disease 2019 (COVID-19) pandemic has expanded exponentially across the globe in less than a year and has impacted healthcare systems, the global economy, societal norms and our daily lives irrevocably. One visible impact is that the use of face masks has been thrust into central focus, becoming a polarising issue that has been divisive, even along political lines.\[[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R1)\]
There is accumulating data that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spreads via airborne or aerosol transmission.\[[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R2),[3](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R3)\] Consequently, most advisory bodies, including the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) have formally recommended widespread usage of surgical or face masks in the community to limit transmission of COVID-19 via droplets and respiratory aerosols.\[[4](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R4),[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R5)\] As SARS-CoV-2 transmission by asymptomatic or pre-symptomatic individuals has been reported, a universal face mask policy has an important role to play in a multi-pronged approach for outbreak control.\[[6](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R6),[7](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R7)\]
Modelling studies have demonstrated that widespread or universal use of face masks in the community has a significant impact on curtailing transmission, with a consequent reduction in mortality rates.\[[8](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R8),[9](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R9)\] Several epidemiologic investigations have also reported the use of face masks being associated with preventing transmission in situations whereby large outbreaks may have otherwise occurred.\[[10](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R10),[11](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R11),[12](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R12)\] Even if face mask use does not eliminate infection risk, it may lower the viral inoculum that an individual is exposed to, resulting in a clinically milder infection.\[[13](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R13),[14](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R14)\]
However, beyond simply ensuring high rates of community mask use, it is equally important to ensure that proper face mask usage and hygiene is followed. Improper use of face masks (e.g. not adequately covering mouth and nose, and not observing hand hygiene) may compromise their protective effect. Community observational studies have evaluated the general public’s proficiency in N95 respirator usage\[[15](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R15)\]; however, there is scant data on compliance to proper face mask usage, which is crucial data required especially during the COVID-19 pandemic.
In this community observational study, we evaluated the proportion of face mask usage, the extent of correct face mask usage and face mask-related hygiene practices among the general public in Singapore.
## METHODS
### Study design
This observational study was conducted from 29 July 2020 to 18 August 2020. During this period, it was mandatory to wear a face mask in all public areas in Singapore (since 15 April 2020), and individuals were subject to a monetary fine of SGD 300 (approximately USD 220) if they were caught not complying with the law. Face shields were allowed as an alternative to face masks in specific situations only such as for children (\<12 years) who have difficulty wearing a mask for a prolonged period and individuals with health conditions who may have difficulty breathing after prolonged mask use. Children below 2 years of age and children with special needs were exempted from wearing face masks.\[[16](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R16)\]
Ten trained study team members were deployed in public areas to observe members of the public anonymously from a distance. The study team members were trained by the principal investigator who designed the study protocol, using clear, written instructions and illustrative examples pertaining to the criteria required for qualification as full compliance to mask wearing. The individuals surveyed were not informed that they were being observed, and no individually identifiable data were collected. The list of locations surveyed was spread across different neighbourhoods in Singapore by randomly selecting 38 mass rapid transit (MRT) stations (the public train system with a dense network of stations serving the entire island) and centring sampling venues around these stations.
### Data collection
Study team members collected data on mask usage using a standardised data collection form. Individuals were observed for a minimum of 5 minutes. The following parameters were recorded: (a) activity that the individual was doing; (b) the type of mask used; (c) whether the mask was used correctly; (d) the method of securing the mask (ear loops, use of loop extender or tied around the head); (e) whether the individual touched the mask or face; and (f) whether hand hygiene was performed before and after touching the mask or face. Demographic data on gender and estimated age (infant: \<2 years, child: 2–5 years, child: 6–20 years and adult: ≥21 years), as well as location data (type of venue and whether venue was crowded) were also collected.
‘Full compliance’ was defined as use of any one of the following type of face masks — fabric mask, surgical mask, face shield, a combination of face mask and face shield, or N95 mask, with the mask or shield fully covering the individual’s mouth and nose, upper boundary moulded over the nose with an appropriate fit and lower boundary below the chin. ‘Poor compliance’ was defined as wearing a mask incorrectly (e.g. with either the mouth or nose exposed, the mask around the chin or neck, the upper or lower boundary is not fitted properly) or using an inappropriate mask (e.g. mask with valve). ‘No mask’ was defined as not wearing any facial covering at all (either face mask or face shield). In accordance with Singapore law, exceptions to mask usage are allowed in specific circumstances of eating, drinking, exercising or driving alone or with family members in the car; these were recorded as instances of ‘allowable non-compliance’ if individuals were wearing a mask inappropriately or not wearing a mask during these circumstances. Individuals were not counted as an instance of non-compliance if they did not put on their mask immediately after eating or drinking. Two main methods were used to assess that a meal was completed: (a) there was no unfinished food or drink left on the table; and (b) there was no further consumption of food or drink for a five-minute observation duration. If the individual was not wearing a face mask or face shield after completing their meal for some time, it was recorded as an instance of non-compliance. Detailed notes on the exact activity and exemption criteria were recorded for arbitration by another member of the study team in ambiguous circumstances. A ‘crowded venue’ was defined as an environment where safe distancing of one metre between individuals is not possible due to the number of people at the venue.
### Statistical methods
All variables analysed were categorical and compared using χ2 test. Univariate and multivariate binary logistic regression analyses were used to determine odds ratios and 95% confidence intervals for variables associated with full mask compliance by comparing full mask compliance against incorrect or absent mask use. Hosmer–Lemeshow test was used to assess the goodness-of-fit of the multivariate model. *P* values \<0.05 were considered significant, and all tests were two-tailed. Analyses were performed using Stata Statistical Software: Release 13 (StataCorp LP, College Station, TX, USA).
### Ethical approval
This study was approved by the institutional review board (National Healthcare Group Domain Specific Review Board; reference number: 2020/00951) with a waiver of informed consent since there was no direct contact with individuals observed, observations were carried out only in public spaces, and no individually identifiable data were collected.
## RESULTS
A total of 3,851 observations were recorded from 367 unique locations in 38 neighbourhoods \[[Supplementary Figure 1](https://pmc.ncbi.nlm.nih.gov/articles/instance/11698284/bin/SMJ-65-674_Suppl1.tif) (118.3KB, tif) , Appendix\]. The location types varied with a mix of food and beverage (F\&B) establishments (both indoor and outdoor), healthcare facilities, public transport, retail and services and open public spaces; with open public spaces being the most common category (1,497 observations or 38.9%) \[[Supplementary Table 1](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#App1), Appendix\]. After excluding children aged \<2 years (29 observations) and children with special needs (one observation) for whom mask usage is not mandated, there were 3,821 observations that were analysed. Of these 3,821 observed individuals, 2,149 (56.2%) were female, 3,569 (93.4%) were adults (≥21 years), 212 (5.5%) were children estimated to be 6–20 years old and 40 (1.0%) were children estimated to be 2–5 years old. As no individual identifiers were collected, it is not known whether any individual was observed more than once at different locations or time points.
The overall proportion of full compliance with mask usage in the study was 79.7%, while that for poor compliance with mask usage and no usage of mask was 14.0% and 6.3%, respectively \[[Table 1](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-t001)\]. After correcting for instances of ‘allowable non-compliance’, the overall proportions of full compliance, poor compliance and no mask usage were 84.5%, 12.9% and 2.6%, respectively. Pitfalls in mask wearing included covering the mouth and nose but having large gaps above or below the mask (235/464, 50.7% of poor compliance observations), not covering the nose (*n* = 140, 30.2%), wearing the mask around the chin (*n* = 67, 14.4%), hanging the mask on the neck (*n* = 7, 1.5%) or dangling the mask on one ear (*n* = 9, 1.9%).
### Table 1.
Overall compliance to mask use by different age groupsa.
| Variable | *n* (%) | Total | | |
|---|---|---|---|---|
| Full complianceb | Poor compliancec | No maskd | | |
| Before excluding allowable reasons for mask non-compliancee | | | | |
| Adult (≥21 years) | 2,848 (79.8) | 505 (14.1) | 217 (6.1) | 3,569 |
| Child (6–20 years) | 177 (83.5) | 23 (10.8) | 11 (5.2) | 212 |
| Child (2–5 years) | 22 (55) | 6 (15) | 12 (30) | 40 |
| Total | 3,047 (79.7) | 534 (14.0) | 240 (6.3) | 3,821 |
| After excluding allowable reasons for mask non-compliancee | | | | |
| Adult (≥21 years) | 2,848 (84.5) | 440 (13.0) | 85 (2.5) | 3,372 |
| Child (6–20 years) | 177 (88.1) | 20 (10.0) | 3 (1.5) | 201 |
| Child (2–5 years) | 22 (66.7) | 4 (12.1) | 7 (21.2) | 33 |
| Total | 3,047 (84.5) | 464 (12.9) | 95 (2.6) | 3,606 |
[Open in a new tab](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/table/singaporemedj.SMJ-2021-010-t001/)
aAge groups refers to estimated age. b‘Full compliance’ with mask usage was defined as using any one of the following type of face mask: fabric mask, surgical mask, face shield, a combination of face mask and face shield, or N95 mask, with the mask or shield fully covering the individual’s mouth and nose, upper boundary moulded over the nose with an appropriate fit and lower boundary below the chin. c‘Poor compliance’ with mask usage was defined as wearing a mask incorrectly (e.g. with either the mouth or nose exposed, the mask around the chin or neck, the upper or lower boundary is not fitted properly) or using an inappropriate mask (e.g. mask with valve). d‘No mask’ was defined as not wearing any facial covering at all. eAccording to the Singapore law, individuals are allowed to remove their mask for the following activities: eating or drinking, exercising or driving alone/with family members in the car
Male gender was associated with incorrect or absent mask use (adjusted odds ratio \[aOR\] 0.69, 95% confidence interval \[CI\] 0.56–0.85) \[[Table 2](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-t002)\]. Use of a surgical mask was associated with improved compliance (aOR 1.99, 95% CI 1.62–2.44) as compared to the use of a fabric mask. Full mask compliance was less frequently observed in spaces that were crowded (OR 0.77, 95% CI 0.64–0.93 in univariate analysis). A detailed analysis of venue categories found that mask compliance was lower in indoor F\&B establishments, healthcare facilities and retail and service venues compared to open public spaces, with a corrected compliance rate of 88.3% in open spaces but falling to 70.0% in indoor F\&B establishments \[[Figure 1](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-f001)\]. Instances of pitfalls in mask wearing in F\&B venues occurred while queueing, ordering food, waiting for food, talking, serving food or cleaning tables.
### Table 2.
Binary logistic regression analysis of factors associated with poor mask compliance or no mask usage.
| Variable | *n* (%) | Univariate analysis | Multivariate analysis | | | |
|---|---|---|---|---|---|---|
| Full compliance (*n*\=3,047) | Poor compliance or no mask use (*n*\=559) | OR (95% CI) for full compliance | *P* | OR ratio (95% CI) for full compliance | *P* | |
| Male gender | 1,269 (41.7) | 289 (51.7) | 0\.67 (0.56–0.80) | \<0.0001 | 0\.69 (0.56–0.85) | \<0.0001 |
| Age group | | | | 0\.007 | | |
| Adult (≥21 years) | 2,848 (93.5) | 524 (93.7) | Ref | Ref | Ref | Ref |
| Child (6–20 years) | 177 (5.8) | 24 (4.3) | 1\.36 (0.88–2.10) | 0\.17 | 1\.52 (0.93–2.49) | 0\.09 |
| Child (2–5 years) | 22 (0.7) | 11 (2.0) | 0\.37 (0.18–0.76) | 0\.007 | 0\.72 (0.24–2.16) | 0\.56 |
| Type of mask | | | | \<0.0001 | | |
| Fabric mask | 1,122 (36.9) | 246 (53.0) | Ref | Ref | Ref | Ref |
| Surgical mask | 1,907 (62.6) | 217 (46.8) | 1\.93 (1.58–2.35) | \<0.0001 | 1\.99 (1.62–2.44) | \<0.001 |
| Face shield | 0 | 1 (0.22) | NA | NA | NA | NA |
| N95 respirator | 4 (0.13) | 0 | NA | NA | NA | NA |
| Both mask and shield | 12 (0.39) | 0 | NA | NA | NA | NA |
| Securing method | | | | 0\.42 | | |
| Ear loop | 2,857 (94.0) | 444 (95.5) | Ref | Ref | Ref | Ref |
| Tied around head | 45 (1.5) | 6 (1.3) | 1\.17 (0.49–2.75) | 0\.73 | 1\.00 (0.42–2.39) | \>0.99 |
| Loop extender | 137 (4.5) | 15 (3.2) | 1\.42 (0.83–2.44) | 0\.21 | 1\.25 (0.72–2.19) | 0\.43 |
| Crowded venuea | 1,031 (33.8) | 223 (39.9) | 0\.77 (0.64–0.93) | 0\.006 | 0\.85 (0.67–1.06) | 0\.15 |
| Type of location | | | | \<0.0001 | | |
| Open public space | 1,258 (41.3) | 166 (29.7) | Ref | Ref | Ref | Ref |
| F\&B (indoor) | 266 (8.7) | 114 (20.4) | 0\.31 (0.23–0.40) | \<0.0001 | 0\.41 (0.29–0.59) | \<0.001 |
| F\&B (outdoor) | 134 (4.4) | 49 (8.8) | 0\.36 (0.25–0.52) | \<0.0001 | 0\.66 (0.40–1.10) | 0\.11 |
| Healthcare facility | 180 (5.9) | 41 (7.3) | 0\.58 (0.40–0.84) | 0\.004 | 0\.61 (0.39–0.94) | 0\.03 |
| Transportation | 672 (22.1) | 89 (15.9) | 1\.00 (0.76–1.31) | 0\.98 | 0\.85 (0.60–1.18) | 0\.33 |
| Retail and services | 537 (17.6) | 100 (17.9) | 0\.71 (0.54–0.93) | 0\.012 | 0\.57 (0.42–0.79) | 0\.001 |
| Type of activity | | | | \<0.0001 | | |
| Standing or sitting idly | 324 (10.8) | 91 (16.3) | Ref | Ref | Ref | Ref |
| Customer service | 206 (6.8) | 16 (2.9) | 3\.62 (2.07–6.33) | \<0.0001 | 3\.62 (1.95–6.75) | \<0.001 |
| Using electronic device | 334 (11.1) | 49 (8.8) | 1\.91 (1.31–2.80) | \<0.0001 | 2\.89 (1.80–4.62) | \<0.001 |
| Preparing food or beverage | 48 (1.6) | 10 (1.8) | 1\.35 (0.66–2.77) | 0\.42 | 1\.63 (0.71–3.72) | 0\.25 |
| Shopping | 412 (13.4) | 64 (11.5) | 1\.81 (1.27–2.57) | 0\.001 | 2\.38 (1.55–3.64) | \<0.001 |
| Smoking | 0 | 17 (3.0) | NA | NA | NA | NA |
| Using transportation service | 229 (7.6) | 23 (4.1) | 2\.80 (1.72–4.55) | \<0.0001 | 2\.19 (1.25–3.82) | 0\.006 |
| Talking | 617 (20.5) | 158 (28.3) | 1\.10 (0.82–1.47) | 0\.53 | 1\.31 (0.93–1.85) | 0\.12 |
| Walking | 843 (28.0) | 131 (23.4) | 1\.81 (1.34–2.43) | \<0.0001 | 1\.55 (1.10–2.19) | 0\.01 |
| Exempted activityb | 34 (1.1) | 0 | NA | NA | NA | NA |
[Open in a new tab](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/table/singaporemedj.SMJ-2021-010-t002/)
*P* values were obtained using *χ*2 test for comparison across categorical variables, and binary logistic regression was used to obtain the individual OR of each variable. Hosmer–Lemeshow test was used for goodness-of-fit of multivariable model (*P* = 0.791). aCrowded venue was defined as an environment where safe distancing of 1 m between individuals is not possible due to the number of people in the venue. bExempted activity includes eating, drinking, exercising or driving, whereby mask use is neither mandated or practical. CI: confidence interval, F\&B: food and beverage establishment, NA: not applicable, OR: odds ratio, Ref: reference variable
### Figure 1.
[Open in a new tab](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/figure/singaporemedj.SMJ-2021-010-f001/)
Graph shows the proportion of individuals observed with full mask compliance (excluding instances of allowable non-compliance) by venue type. F\&B: food and beverage establishment (e.g. restaurant, hawker centre, food court).
An analysis of face or mask touching behaviour showed that a large proportion of individuals touched their mask (10.7%) or face (13.5%) during the observations \[[Table 3](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-t003)\]. The most common area of the face touched was the head (35.6%), followed by the mouth (21.4%) \[[Figure 2](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-f002)\]. Of significant concern is the small number of individuals who performed hand hygiene before (*n* = 2) and after (*n* = 3) touching their mask or face \[[Table 3](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-t003)\]. Only one individual performed hand hygiene both before and after as per the recommended infection control precautions.
### Table 3.
Frequency of mask or face touching behaviour and hand hygiene by age.
| Age groupa | *n* (%) | | | |
|---|---|---|---|---|
| Touched mask | Touched face | Hand hygiene beforeb | Hand hygiene afterb | |
| Adult (≥21 years) | 377 (10.6) | 466 (13.1) | 2 (0.28) | 3 (0.42) |
| Child (6–20 years) | 30 (14.2) | 38 (17.9) | 0 | 0 |
| Child (2–5 years) | 3 (7.5) | 10 (25) | 0 | 0 |
| Total | 410 (10.7) | 514 (13.5) | 2 (0.25) | 3 (0.38) |
[Open in a new tab](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/table/singaporemedj.SMJ-2021-010-t003/)
aAge group refers to estimated age. bPercentage is expressed using the denominator of the number of individuals who touched either their mask or face.
### Figure 2.
[Open in a new tab](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/figure/singaporemedj.SMJ-2021-010-f002/)
Graph shows the frequency of different areas of the face touched during face-touching observations. Percentages are expressed using the denominator of the number of individuals who touched their face, with some observed to have touched more than one area. ‘Face’ refers to the areas of the face other than the mouth, nose, ears or eyes.
Being fully compliant with mask usage was associated with a lower rate of face or mask touching behaviour \[[Tables 3](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-t003) and [4](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-t004)\]. Children were also more likely to touch their mask or face. The use of a surgical mask compared to a fabric mask was significantly associated with a lower rate of touching one’s face or mask (OR 0.84, 95% CI 0.71–0.99). No significant differences were identified between different methods of wearing a face mask (e.g. ear loops, tying behind one’s head or use of a dedicated loop extender). Being in a crowded area was associated with increased face or mask touching behaviour, similar to the effect on lowered mask compliance.
### Table 4.
Factors associated with mask or face touching behaviour.
| Variable | *n* (%) | Odds ratio (95% CI) | *P* | |
|---|---|---|---|---|
| Mask or face touching (*n*\=789) | No mask or face touching (*n*\=3,032) | | | |
| Male gender | 337 (42.7) | 1335 (44.0) | 0\.95 (0.81–1.11) | 0\.51 |
| Age groupa | | | | 0\.001 |
| Adult (≥21 years) | 714 (90.5) | 2855 (94.2) | Ref | Ref |
| Child (6–20 years) | 62 (7.9) | 150 (5.0) | 1\.65 (1.22–2.25) | 0\.001 |
| Child (2–5 years) | 13 (1.7) | 27 (0.9) | 1\.93 (0.99–3.75) | 0\.054 |
| Type of mask | | | | 0\.07 |
| Fabric mask | 296 (42.8) | 1106 (38.3) | Ref | Ref |
| Surgical mask | 396 (57.2) | 1763 (61.1) | 0\.84 (0.71–0.99) | 0\.04 |
| Face shield | 0 | 2 (0.07) | NA | NA |
| N95 respirator | 0 | 4 (0.14) | NA | NA |
| Both mask and shield | 0 | 12 (0.42) | NA | NA |
| Securing method | | | | 0\.52 |
| Ear loop | 660 (94.7) | 2704 (93.9) | Ref | Ref |
| Tied around head | 7 (1.0) | 45 (1.6) | 0\.64 (0.29–1.42) | 0\.27 |
| Loop extender | 30 (4.3) | 130 (4.5) | 0\.95 (0.63–1.42) | 0\.79 |
| Full mask compliance | 506 (64.1) | 2541 (83.8) | 0\.35 (0.29–0.41) | \<0.0001 |
| Crowded venueb | 311 (39.4) | 1044 (34.4) | 1\.24 (1.05–1.46) | 0\.009 |
[Open in a new tab](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/table/singaporemedj.SMJ-2021-010-t004/)
*P* values were obtained using *χ*2 test for comparison across categorical variables, and binary logistic regression was used to obtain the individual odds ratio of each variable. aAge group refers to estimated age. bCrowded venue was defined as an environment where safe distancing of 1 m between individuals is not possible due to the number of people in the venue. CI: confidence interval, NA: not applicable, Ref: reference variable
## DISCUSSION
This study assessed the compliance rate and appropriate use of face masks by the general public across a broad range of public venues. The overall rate of mask compliance was high at 84.5%, which is higher than reported rates in other countries such as the United States, the United Kingdom and Australia.\[[17](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R17)\] This is likely largely due to strict legislation mandating mask usage in Singapore. Other contributing factors could include active enforcement by safe distancing ambassadors (designated public health officers who patrol public spaces to ensure compliance with public health measures) and high level of public trust in the Singapore government. Nonetheless, we identified several problem areas in mask usage and personal hygiene.
First, we identified key demographic groups that may benefit from improved targeted public health messaging (men for appropriate mask usage and children for face and mask touching behaviour). This finding of lower mask-wearing compliance rates among men is similar to the findings of Haischer and colleagues in a similar community mask audit study conducted in the United States.\[[18](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R18)\]
Second, we identified several venues (indoor F\&B establishments, healthcare facilities and retail and services) where mask usage is comparably lower, and these places will benefit from improved surveillance and/or reminders to improve compliance. The finding that more crowded areas are associated with decreased mask compliance and increased face and mask touching behaviour is concerning and unexpected, given that the transmission risk is expected to be the greatest in crowded areas.\[[19](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R19)\] We hypothesise that ventilation may be comparably poorer in crowded areas, resulting in more sweating and discomfort for mask users, and hence, higher rates of mask or face touching for mask adjustment, leading to poor compliance. An alternative explanation could be that in crowded indoor areas, people feel like they are less likely to be caught or policed for non-compliance, resulting in more lax behaviour. Systemic interventions should be considered to ensure that such situations are minimised, for example optimising ventilation and air-flow, imposing venue capacity limitations or increasing surveillance.\[[19](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R19)\]
Third, the finding of almost zero hand hygiene practised before and after face or mask touching is of concern and should be emphasised in future public health messaging. Avoidance of touching of one’s eyes, mouth and nose is advised to prevent the inoculation of SARS-CoV-2 by touch after contact with contaminated surfaces,\[[20](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R20)\] and thus hand hygiene before and after face or mask touching is an important instruction that should be disseminated. Theoretical concern has also been raised that the use of face masks would be associated with an increased incidence of users touching their face (e.g. to adjust the mask or to scratch their nose or mouth) as a result of the discomfort associated with mask wearing, resulting in a counterproductive effect. In contrast, a large international cross-sectional study by Chen *et al.*, which compared the observations of 2,887 individuals during the pandemic with 4,699 individuals before the pandemic, showed that mask usage was associated with reduced face-touching behaviour.\[[21](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R21)\] While we had no pre-pandemic data to compare the incidence of face-touching behaviour, in our study, we found that individuals who were fully compliant with mask usage had less face-touching behaviour compared to those who had poor compliance or did not use a mask, suggesting that face mask use was associated with reduced face-touching behaviour, though this association could be explained by an overall more conscientious attitude towards hygiene rather than direct causation. Of note, face-touching rates in our study were much higher than those reported by Chen *et al*. and comparable to their reported pre-pandemic rates (4.1%, 11.2% and 11.4% in China, South Korea and Europe, respectively).
The evidence for the optimal mask for use in healthcare settings remains inconclusive, with debate over whether a particulate respirator (e.g. filtering face piece \[FFP\]-2 or N95 respirator) is necessary in all healthcare settings.\[[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R2),[22](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R22)\] However, it is clear that widespread adoption of particulate respirators for the general public is not recommended, given the issues with resource limitations, requirement for fit testing and poor mask-wearing proficiency.\[[15](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R15)\] Public health messaging that N95 respirators are not required for general use was consistent, and we note that only four observations of N95 mask use were made.
Non-traditional or alternative materials for masks (such as cotton, silk or linen) have been evaluated in *in vitro* studies of filtration efficacy, and while they may be less effective than conventional surgical masks,\[[23](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R23)\] they nonetheless proffer some degree of protection and may provide advantages in terms of comfort and availability. However, in this study, we observed that the use of fabric masks, as compared to surgical masks, is associated with poorer mask compliance and increased face or mask touching behaviour, and this is concerning and merits further evaluation. One possible explanation is that there were unmeasured confounding factors, and the demographics of fabric mask users could be different from that of surgical mask users (e.g. they could be less careful or informed, and hence paid less attention to infection control precautions).
Our study has several limitations. First, as it was only done in a single country, the findings may not necessarily be applicable to other settings, especially in countries where mask policy is not backed by law, or where other cultural or political influences affect the decision to use a mask. Second, we did not collect individually identifiable information or conduct detailed individual surveys, and hence could not further narrow down the demographic factors associated with mask compliance or evaluate the general public’s knowledge and attitudes towards mask use. For that same reason, the categorised age groups were only an estimate based on the child’s appearance and there may have been mis-classification in some instances. Furthermore, observations were conducted during daytime office hours only; hence, we did not explore the impact of time of day on mask-wearing behaviour. Third, while effort was made to ensure a good distribution of locations across the country, there was no systematic selection of sampling venues, and venues were instead selected on a best-effort basis by study team members based on proximity to the allocated MRT station. Nonetheless, the amount of bias this may have introduced should be minimal. Lastly, we did not conduct any statistical testing or external validation to assess if there was significant inter-observer variability among study team members; however, we assess that the amount of bias introduced by this factor to be very minimal.
In conclusion, compliance to mask usage was high during the COVID-19 pandemic in Singapore. However, we identified key problem areas to optimise future public health messaging, including high-risk venues where mask usage should be reinforced and the importance of hand hygiene before and after touching of one’s mask or face. Future studies can examine behavioural interventions at crowded areas to improve compliance. Similar community studies should be conducted in other settings to better inform and tailor public health policies.
### Conflicts of interest
Vasoo S is a member of the SMJ Editorial Board and was not involved in the publication decision of this article. The abovementioned funders played no role in the design and conduct of the study; the collection, management, analysis and interpretation of the data; the preparation, review or approval of the manuscript, and the decision to submit the manuscript for publication.
### Supplemental digital content
Appendix at <https://links.lww.com/SMJ/xx>
Supplementary Figure. 1
Spread of locations surveyed outlined on the Singapore map.
[SMJ-65-674\_Suppl1.tif](https://pmc.ncbi.nlm.nih.gov/articles/instance/11698284/bin/SMJ-65-674_Suppl1.tif) (118.3KB, tif)
## APPENDIX
### Supplementary Table 1.
Breakdown of location types surveyed.
| Type of location | Number of observations | Percentage |
|---|---|---|
| F\&B (Indoor) | 493 | 12\.8 |
| F\&B (Outdoor) | 222 | 5\.8 |
| Healthcare Facilities | 225 | 5\.8 |
| Public Transport | 771 | 20\.0 |
| Public Spaces | 1497 | 38\.9 |
| Retail & Services | 643 | 16\.7 |
| **Total** | **3851** | 100 |
[Open in a new tab](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/table/d67e1790/)
F\&B: food & beverage establishment (e.g. restaurant, hawker centre, food court)
## Funding Statement
This study was funded by the National Health Group–National Centre for Infectious Diseases COVID-19 Centre Grant (COVID19 CG0002). Ng OT is supported by the National Medical Research Council (NMRC) Clinician Scientist Award (MOH-000276). Marimuthu K is supported by the NMRC Clinician Scientist-Individual Research Grant (CIRG18Nov-0034).
## REFERENCES
- 1\.
Flaskerud JH. Masks, politics, culture and health. Issues Ment Health Nurs. 2020;41:846–9. doi: 10.1080/01612840.2020.1779883.
\[[DOI](https://doi.org/10.1080/01612840.2020.1779883)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32644832/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Issues%20Ment%20Health%20Nurs&title=Masks,%20politics,%20culture%20and%20health&author=JH%20Flaskerud&volume=41&publication_year=2020&pages=846-9&pmid=32644832&doi=10.1080/01612840.2020.1779883&)\]
- 2\.
Ong SWX, Coleman KK, Chia PY, Thoon KC, Pada S, Venkatachalam I, et al. Transmission modes of severe acute respiratory syndrome coronavirus 2 and implications on infection control: A review. Singapore Med J. 2022;63:61–7. doi: 10.11622/smedj.2020114.
\[[DOI](https://doi.org/10.11622/smedj.2020114)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC9251227/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32729311/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Singapore%20Med%20J&title=Transmission%20modes%20of%20severe%20acute%20respiratory%20syndrome%20coronavirus%202%20and%20implications%20on%20infection%20control:%20A%20review&author=SWX%20Ong&author=KK%20Coleman&author=PY%20Chia&author=KC%20Thoon&author=S%20Pada&volume=63&publication_year=2022&pages=61-7&pmid=32729311&doi=10.11622/smedj.2020114&)\]
- 3\.
Sommerstein R, Fux CA, Vuichard-Gysin D, Abbas M, Marschall J, Balmelli C, et al. Risk of SARS-CoV-2 transmission by aerosols, the rational use of masks, and protection of healthcare workers from COVID-19. Antimicrob Resist Infect Control. 2020;9:100. doi: 10.1186/s13756-020-00763-0.
\[[DOI](https://doi.org/10.1186/s13756-020-00763-0)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7336106/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32631450/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Antimicrob%20Resist%20Infect%20Control&title=Risk%20of%20SARS-CoV-2%20transmission%20by%20aerosols,%20the%20rational%20use%20of%20masks,%20and%20protection%20of%20healthcare%20workers%20from%20COVID-19&author=R%20Sommerstein&author=CA%20Fux&author=D%20Vuichard-Gysin&author=M%20Abbas&author=J%20Marschall&volume=9&publication_year=2020&pages=100&pmid=32631450&doi=10.1186/s13756-020-00763-0&)\]
- 4\.
Advice on the use of masks in the context of COVID-19: World Health Organization. 2020. \[Last accessed on 2020 Aug 18\]. \[Updated 2020 Jun 05\] Available from:<https://apps.who.int/iris/bitstream/handle/10665/332293/WHO-2019-nCov-IPC_Masks-2020.4-eng.pdf> .
- 5\.
Considerations for Wearing Masks: Centers for Disease Control and Prevention. 2020. \[Last accessed on 2020 Aug 18\]. \[Updated 2020 Aug 07\] Available from:<https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html> .
- 6\.
Wei WE, Li Z, Chiew CJ, Yong SE, Toh MP, Lee VJ. Presymptomatic transmission of SARS-CoV-2-Singapore, January 23-March 16, 2020. MMWR Morb Mortal Wkly Rep. 2020;69:411–5. doi: 10.15585/mmwr.mm6914e1.
\[[DOI](https://doi.org/10.15585/mmwr.mm6914e1)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7147908/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32271722/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=MMWR%20Morb%20Mortal%20Wkly%20Rep&title=Presymptomatic%20transmission%20of%20SARS-CoV-2-Singapore,%20January%2023-March%2016,%202020&author=WE%20Wei&author=Z%20Li&author=CJ%20Chiew&author=SE%20Yong&author=MP%20Toh&volume=69&publication_year=2020&pages=411-5&pmid=32271722&doi=10.15585/mmwr.mm6914e1&)\]
- 7\.
Furukawa NW, Brooks JT, Sobel J. Evidence supporting transmission of severe acute respiratory syndrome coronavirus 2 while presymptomatic or asymptomatic. Emerg Infect Dis. 2020;26:e201595. doi: 10.3201/eid2607.201595.
\[[DOI](https://doi.org/10.3201/eid2607.201595)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7323549/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32364890/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Emerg%20Infect%20Dis&title=Evidence%20supporting%20transmission%20of%20severe%20acute%20respiratory%20syndrome%20coronavirus%202%20while%20presymptomatic%20or%20asymptomatic&author=NW%20Furukawa&author=JT%20Brooks&author=J%20Sobel&volume=26&publication_year=2020&pages=e201595&pmid=32364890&doi=10.3201/eid2607.201595&)\]
- 8\.
Eikenberry SE, Mancuso M, Iboi E, Phan T, Eikenberry K, Kuang Y, et al. To mask or not to mask: Modeling the potential for face mask use by the general public to curtail the COVID-19 pandemic. Infect Dis Model. 2020;5:293–308. doi: 10.1016/j.idm.2020.04.001.
\[[DOI](https://doi.org/10.1016/j.idm.2020.04.001)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7186508/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32355904/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Infect%20Dis%20Model&title=To%20mask%20or%20not%20to%20mask:%20Modeling%20the%20potential%20for%20face%20mask%20use%20by%20the%20general%20public%20to%20curtail%20the%20COVID-19%20pandemic&author=SE%20Eikenberry&author=M%20Mancuso&author=E%20Iboi&author=T%20Phan&author=K%20Eikenberry&volume=5&publication_year=2020&pages=293-308&pmid=32355904&doi=10.1016/j.idm.2020.04.001&)\]
- 9\.
Worby CJ, Chang HH. Face mask use in the general population and optimal resource allocation during the COVID-19 pandemic. Nat Commun. 2020;11:4049. doi: 10.1038/s41467-020-17922-x.
\[[DOI](https://doi.org/10.1038/s41467-020-17922-x)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7426871/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32792562/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Nat%20Commun&title=Face%20mask%20use%20in%20the%20general%20population%20and%20optimal%20resource%20allocation%20during%20the%20COVID-19%20pandemic&author=CJ%20Worby&author=HH%20Chang&volume=11&publication_year=2020&pages=4049&pmid=32792562&doi=10.1038/s41467-020-17922-x&)\]
- 10\.
Schwartz KL, Murti M, Finkelstein M, Leis JA, Fitzgerald-Husek A, Bourns L, et al. Lack of COVID-19 transmission on an international flight. CMAJ. 2020;192:E410. doi: 10.1503/cmaj.75015.
\[[DOI](https://doi.org/10.1503/cmaj.75015)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7162437/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32392504/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=CMAJ&title=Lack%20of%20COVID-19%20transmission%20on%20an%20international%20flight&author=KL%20Schwartz&author=M%20Murti&author=M%20Finkelstein&author=JA%20Leis&author=A%20Fitzgerald-Husek&volume=192&publication_year=2020&pages=E410&pmid=32392504&doi=10.1503/cmaj.75015&)\]
- 11\.
Hendrix MJ, Walde C, Findley K, Trotman R. Absence of apparent transmission of SARS-CoV-2 from two stylists after exposure at a hair salon with a Universal Face Covering Policy —Springfield, Missouri, May 2020. MMWR Morb Mortal Wkly Rep. 2020;69:930–2. doi: 10.15585/mmwr.mm6928e2.
\[[DOI](https://doi.org/10.15585/mmwr.mm6928e2)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32673300/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=MMWR%20Morb%20Mortal%20Wkly%20Rep&title=Absence%20of%20apparent%20transmission%20of%20SARS-CoV-2%20from%20two%20stylists%20after%20exposure%20at%20a%20hair%20salon%20with%20a%20Universal%20Face%20Covering%20Policy%20%E2%80%94Springfield,%20Missouri,%20May%202020&author=MJ%20Hendrix&author=C%20Walde&author=K%20Findley&author=R%20Trotman&volume=69&publication_year=2020&pages=930-2&pmid=32673300&doi=10.15585/mmwr.mm6928e2&)\]
- 12\.
Cheng VC, Wong SC, Chuang VW, So SY, Chen JH, Sridhar S, et al. The role of community-wide wearing of face mask for control of coronavirus disease 2019 (COVID-19) epidemic due to SARS-CoV-2. J Infect. 2020;81:107–14. doi: 10.1016/j.jinf.2020.04.024.
\[[DOI](https://doi.org/10.1016/j.jinf.2020.04.024)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7177146/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32335167/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=J%20Infect&title=The%20role%20of%20community-wide%20wearing%20of%20face%20mask%20for%20control%20of%20coronavirus%20disease%202019%20\(COVID-19\)%20epidemic%20due%20to%20SARS-CoV-2&author=VC%20Cheng&author=SC%20Wong&author=VW%20Chuang&author=SY%20So&author=JH%20Chen&volume=81&publication_year=2020&pages=107-14&pmid=32335167&doi=10.1016/j.jinf.2020.04.024&)\]
- 13\.
Guallar MP, Meirino R, Donat-Vargas C, Corral O, Jouve N, Soriano V. Inoculum at the time of SARS-CoV-2 exposure and risk of disease severity. Int J Infect Dis. 2020;97:290–2. doi: 10.1016/j.ijid.2020.06.035.
\[[DOI](https://doi.org/10.1016/j.ijid.2020.06.035)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7293836/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32553720/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Int%20J%20Infect%20Dis&title=Inoculum%20at%20the%20time%20of%20SARS-CoV-2%20exposure%20and%20risk%20of%20disease%20severity&author=MP%20Guallar&author=R%20Meirino&author=C%20Donat-Vargas&author=O%20Corral&author=N%20Jouve&volume=97&publication_year=2020&pages=290-2&pmid=32553720&doi=10.1016/j.ijid.2020.06.035&)\]
- 14\.
Gandhi M, Beyrer C, Goosby E. Masks do more than protect others during covid-19: Reducing the inoculum of SARS-CoV-2 to protect the wearer. J Gen Intern Med. 2020;35:3063–6. doi: 10.1007/s11606-020-06067-8.
\[[DOI](https://doi.org/10.1007/s11606-020-06067-8)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7393808/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32737790/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=J%20Gen%20Intern%20Med&title=Masks%20do%20more%20than%20protect%20others%20during%20covid-19:%20Reducing%20the%20inoculum%20of%20SARS-CoV-2%20to%20protect%20the%20wearer&author=M%20Gandhi&author=C%20Beyrer&author=E%20Goosby&volume=35&publication_year=2020&pages=3063-6&pmid=32737790&doi=10.1007/s11606-020-06067-8&)\]
- 15\.
Yeung W, Ng K, Fong JMN, Sng J, Tai BC, Chia SE. Assessment of proficiency of n95 mask donning among the general public in Singapore. JAMA Netw Open. 2020;3:e209670. doi: 10.1001/jamanetworkopen.2020.9670.
\[[DOI](https://doi.org/10.1001/jamanetworkopen.2020.9670)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7240349/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32432708/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=JAMA%20Netw%20Open&title=Assessment%20of%20proficiency%20of%20n95%20mask%20donning%20among%20the%20general%20public%20in%20Singapore&author=W%20Yeung&author=K%20Ng&author=JMN%20Fong&author=J%20Sng&author=BC%20Tai&volume=3&publication_year=2020&pages=e209670&pmid=32432708&doi=10.1001/jamanetworkopen.2020.9670&)\]
- 16\.
Guidance for use of masks and face shields: Ministry of Health. Singapore: 2020. \[Last accessed on 2020 Aug 18\]. Available from:<https://www.moh.gov.sg/news-highlights/details/guidance-for-use-of-masks-and-face-shields> .
\[[Google Scholar](https://scholar.google.com/scholar_lookup?title=Guidance%20for%20use%20of%20masks%20and%20face%20shields:%20Ministry%20of%20Health&publication_year=2020&)\]
- 17\.
MacIntyre CR, Nguyen PY, Chughtai AA, Trent M, Gerber B, Steinhofel K, et al. Mask use, risk-mitigation behaviours and pandemic fatigue during the COVID-19 pandemic in five cities in Australia, the UK and USA: A cross-sectional survey. Int J Infect Dis. 2021;106:199–207. doi: 10.1016/j.ijid.2021.03.056.
\[[DOI](https://doi.org/10.1016/j.ijid.2021.03.056)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7985682/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/33771668/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Int%20J%20Infect%20Dis&title=Mask%20use,%20risk-mitigation%20behaviours%20and%20pandemic%20fatigue%20during%20the%20COVID-19%20pandemic%20in%20five%20cities%20in%20Australia,%20the%20UK%20and%20USA:%20A%20cross-sectional%20survey&author=CR%20MacIntyre&author=PY%20Nguyen&author=AA%20Chughtai&author=M%20Trent&author=B%20Gerber&volume=106&publication_year=2021&pages=199-207&pmid=33771668&doi=10.1016/j.ijid.2021.03.056&)\]
- 18\.
Haischer MH, Beilfuss R, Hart MR, Opielinski L, Wrucke D, Zirgaitis G, et al. Who is wearing a mask?Gender-, age-, and location-related differences during the COVID-19 pandemic. PLoS One. 2020;15:e0240785. doi: 10.1371/journal.pone.0240785.
\[[DOI](https://doi.org/10.1371/journal.pone.0240785)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7561164/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/33057375/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=PLoS%20One&title=Who%20is%20wearing%20a%20mask?Gender-,%20age-,%20and%20location-related%20differences%20during%20the%20COVID-19%20pandemic&author=MH%20Haischer&author=R%20Beilfuss&author=MR%20Hart&author=L%20Opielinski&author=D%20Wrucke&volume=15&publication_year=2020&pages=e0240785&pmid=33057375&doi=10.1371/journal.pone.0240785&)\]
- 19\.
Morawska L, Tang JW, Bahnfleth W, Bluyssen PM, Boerstra A, Buonanno G, et al. How can airborne transmission of COVID-19 indoors be minimised? Environ Int. 2020;142:105832. doi: 10.1016/j.envint.2020.105832.
\[[DOI](https://doi.org/10.1016/j.envint.2020.105832)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7250761/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32521345/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Environ%20Int&title=How%20can%20airborne%20transmission%20of%20COVID-19%20indoors%20be%20minimised?&author=L%20Morawska&author=JW%20Tang&author=W%20Bahnfleth&author=PM%20Bluyssen&author=A%20Boerstra&volume=142&publication_year=2020&pages=105832&pmid=32521345&doi=10.1016/j.envint.2020.105832&)\]
- 20\.
Coronavirus disease (COVID-19) advice for the public: World Health Organization. 2020. \[Last accessed on 2020 Aug 18\]. Available from:<https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public> .
- 21\.
Chen YJ, Qin G, Chen J, Xu JL, Feng DY, Wu XY, et al. Comparison of face-touching behaviors before and during the coronavirus disease 2019 pandemic. JAMA Netw Open. 2020;3:e2016924. doi: 10.1001/jamanetworkopen.2020.16924.
\[[DOI](https://doi.org/10.1001/jamanetworkopen.2020.16924)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC12124488/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32725247/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=JAMA%20Netw%20Open&title=Comparison%20of%20face-touching%20behaviors%20before%20and%20during%20the%20coronavirus%20disease%202019%20pandemic&author=YJ%20Chen&author=G%20Qin&author=J%20Chen&author=JL%20Xu&author=DY%20Feng&volume=3&publication_year=2020&pages=e2016924&pmid=32725247&doi=10.1001/jamanetworkopen.2020.16924&)\]
- 22\.
Conly J, Seto WH, Pittet D, Holmes A, Chu M, Hunter PR, et al. Use of medical face masks versus particulate respirators as a component of personal protective equipment for health care workers in the context of the COVID-19 pandemic. Antimicrob Resist Infect Control. 2020;9:126. doi: 10.1186/s13756-020-00779-6.
\[[DOI](https://doi.org/10.1186/s13756-020-00779-6)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7406874/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32762735/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Antimicrob%20Resist%20Infect%20Control&title=Use%20of%20medical%20face%20masks%20versus%20particulate%20respirators%20as%20a%20component%20of%20personal%20protective%20equipment%20for%20health%20care%20workers%20in%20the%20context%20of%20the%20COVID-19%20pandemic&author=J%20Conly&author=WH%20Seto&author=D%20Pittet&author=A%20Holmes&author=M%20Chu&volume=9&publication_year=2020&pages=126&pmid=32762735&doi=10.1186/s13756-020-00779-6&)\]
- 23\.
Wilson AM, Abney SE, King MF, Weir MH, Lopez-Garcia M, Sexton JD, et al. COVID-19 and use of non-traditional masks: How do various materials compare in reducing the risk of infection for mask wearers? J Hosp Infect. 2020;105:640–2. doi: 10.1016/j.jhin.2020.05.036.
\[[DOI](https://doi.org/10.1016/j.jhin.2020.05.036)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7264937/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32502581/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=J%20Hosp%20Infect&title=COVID-19%20and%20use%20of%20non-traditional%20masks:%20How%20do%20various%20materials%20compare%20in%20reducing%20the%20risk%20of%20infection%20for%20mask%20wearers?&author=AM%20Wilson&author=SE%20Abney&author=MF%20King&author=MH%20Weir&author=M%20Lopez-Garcia&volume=105&publication_year=2020&pages=640-2&pmid=32502581&doi=10.1016/j.jhin.2020.05.036&)\]
## Associated Data
*This section collects any data citations, data availability statements, or supplementary materials included in this article.*
### Supplementary Materials
Supplementary Figure. 1
Spread of locations surveyed outlined on the Singapore map.
[SMJ-65-674\_Suppl1.tif](https://pmc.ncbi.nlm.nih.gov/articles/instance/11698284/bin/SMJ-65-674_Suppl1.tif) (118.3KB, tif)
***
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| Readable Markdown | ## Abstract
### Introduction:
Widespread mask use is an important intervention for control of the coronavirus disease 2019 pandemic. However, data on the factors affecting mask use are lacking. In this observational study, we evaluated the proportion of and factors influencing face mask use and related hygiene practices.
### Methods:
We observed randomly selected members from the public in 367 venues across Singapore, and recorded the proportion of individuals with full compliance with mask use and mask hygiene (hand hygiene before and after touching the mask or face). Logistic regression analyses were used to determine variables associated with mask and hand hygiene compliance.
### Results:
We made 3,821 observations — 2,149 (56.2%) females, 3,569 (93.4%) adults (≥21 years), 212 (5.5%) children (6–20 years) and 40 (1.0%) children (2–5 years). The overall full compliance rate (correct mask use), poor compliance rate (incorrect mask use) and absent mask use were 84.5%, 12.9% and 2.6%, respectively. The factors — male gender, fabric mask usage and crowded indoor venues — were associated with lower mask compliance. Face or mask touching behaviour was observed in 10.7% and 13.7% of individuals observed, respectively. Only one individual performed hand hygiene before and after touching the mask.
### Conclusion:
The rate of mask compliance was high, probably due to legislation mandating mask usage. However, specific factors and crowded indoor venues associated with lower mask compliance were identified. We also noted an issue with the absence of hand hygiene before and after face or mask touching. These issues may benefit from targeted public health messaging.
**Keywords:** COVID-19, face mask, mask usage, public health, SARS-CoV-2
## INTRODUCTION
The coronavirus disease 2019 (COVID-19) pandemic has expanded exponentially across the globe in less than a year and has impacted healthcare systems, the global economy, societal norms and our daily lives irrevocably. One visible impact is that the use of face masks has been thrust into central focus, becoming a polarising issue that has been divisive, even along political lines.\[[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R1)\]
There is accumulating data that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spreads via airborne or aerosol transmission.\[[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R2),[3](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R3)\] Consequently, most advisory bodies, including the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) have formally recommended widespread usage of surgical or face masks in the community to limit transmission of COVID-19 via droplets and respiratory aerosols.\[[4](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R4),[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R5)\] As SARS-CoV-2 transmission by asymptomatic or pre-symptomatic individuals has been reported, a universal face mask policy has an important role to play in a multi-pronged approach for outbreak control.\[[6](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R6),[7](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R7)\]
Modelling studies have demonstrated that widespread or universal use of face masks in the community has a significant impact on curtailing transmission, with a consequent reduction in mortality rates.\[[8](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R8),[9](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R9)\] Several epidemiologic investigations have also reported the use of face masks being associated with preventing transmission in situations whereby large outbreaks may have otherwise occurred.\[[10](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R10),[11](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R11),[12](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R12)\] Even if face mask use does not eliminate infection risk, it may lower the viral inoculum that an individual is exposed to, resulting in a clinically milder infection.\[[13](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R13),[14](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R14)\]
However, beyond simply ensuring high rates of community mask use, it is equally important to ensure that proper face mask usage and hygiene is followed. Improper use of face masks (e.g. not adequately covering mouth and nose, and not observing hand hygiene) may compromise their protective effect. Community observational studies have evaluated the general public’s proficiency in N95 respirator usage\[[15](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R15)\]; however, there is scant data on compliance to proper face mask usage, which is crucial data required especially during the COVID-19 pandemic.
In this community observational study, we evaluated the proportion of face mask usage, the extent of correct face mask usage and face mask-related hygiene practices among the general public in Singapore.
## METHODS
### Study design
This observational study was conducted from 29 July 2020 to 18 August 2020. During this period, it was mandatory to wear a face mask in all public areas in Singapore (since 15 April 2020), and individuals were subject to a monetary fine of SGD 300 (approximately USD 220) if they were caught not complying with the law. Face shields were allowed as an alternative to face masks in specific situations only such as for children (\<12 years) who have difficulty wearing a mask for a prolonged period and individuals with health conditions who may have difficulty breathing after prolonged mask use. Children below 2 years of age and children with special needs were exempted from wearing face masks.\[[16](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R16)\]
Ten trained study team members were deployed in public areas to observe members of the public anonymously from a distance. The study team members were trained by the principal investigator who designed the study protocol, using clear, written instructions and illustrative examples pertaining to the criteria required for qualification as full compliance to mask wearing. The individuals surveyed were not informed that they were being observed, and no individually identifiable data were collected. The list of locations surveyed was spread across different neighbourhoods in Singapore by randomly selecting 38 mass rapid transit (MRT) stations (the public train system with a dense network of stations serving the entire island) and centring sampling venues around these stations.
### Data collection
Study team members collected data on mask usage using a standardised data collection form. Individuals were observed for a minimum of 5 minutes. The following parameters were recorded: (a) activity that the individual was doing; (b) the type of mask used; (c) whether the mask was used correctly; (d) the method of securing the mask (ear loops, use of loop extender or tied around the head); (e) whether the individual touched the mask or face; and (f) whether hand hygiene was performed before and after touching the mask or face. Demographic data on gender and estimated age (infant: \<2 years, child: 2–5 years, child: 6–20 years and adult: ≥21 years), as well as location data (type of venue and whether venue was crowded) were also collected.
‘Full compliance’ was defined as use of any one of the following type of face masks — fabric mask, surgical mask, face shield, a combination of face mask and face shield, or N95 mask, with the mask or shield fully covering the individual’s mouth and nose, upper boundary moulded over the nose with an appropriate fit and lower boundary below the chin. ‘Poor compliance’ was defined as wearing a mask incorrectly (e.g. with either the mouth or nose exposed, the mask around the chin or neck, the upper or lower boundary is not fitted properly) or using an inappropriate mask (e.g. mask with valve). ‘No mask’ was defined as not wearing any facial covering at all (either face mask or face shield). In accordance with Singapore law, exceptions to mask usage are allowed in specific circumstances of eating, drinking, exercising or driving alone or with family members in the car; these were recorded as instances of ‘allowable non-compliance’ if individuals were wearing a mask inappropriately or not wearing a mask during these circumstances. Individuals were not counted as an instance of non-compliance if they did not put on their mask immediately after eating or drinking. Two main methods were used to assess that a meal was completed: (a) there was no unfinished food or drink left on the table; and (b) there was no further consumption of food or drink for a five-minute observation duration. If the individual was not wearing a face mask or face shield after completing their meal for some time, it was recorded as an instance of non-compliance. Detailed notes on the exact activity and exemption criteria were recorded for arbitration by another member of the study team in ambiguous circumstances. A ‘crowded venue’ was defined as an environment where safe distancing of one metre between individuals is not possible due to the number of people at the venue.
### Statistical methods
All variables analysed were categorical and compared using χ2 test. Univariate and multivariate binary logistic regression analyses were used to determine odds ratios and 95% confidence intervals for variables associated with full mask compliance by comparing full mask compliance against incorrect or absent mask use. Hosmer–Lemeshow test was used to assess the goodness-of-fit of the multivariate model. *P* values \<0.05 were considered significant, and all tests were two-tailed. Analyses were performed using Stata Statistical Software: Release 13 (StataCorp LP, College Station, TX, USA).
### Ethical approval
This study was approved by the institutional review board (National Healthcare Group Domain Specific Review Board; reference number: 2020/00951) with a waiver of informed consent since there was no direct contact with individuals observed, observations were carried out only in public spaces, and no individually identifiable data were collected.
## RESULTS
A total of 3,851 observations were recorded from 367 unique locations in 38 neighbourhoods \[[Supplementary Figure 1](https://pmc.ncbi.nlm.nih.gov/articles/instance/11698284/bin/SMJ-65-674_Suppl1.tif) (118.3KB, tif) , Appendix\]. The location types varied with a mix of food and beverage (F\&B) establishments (both indoor and outdoor), healthcare facilities, public transport, retail and services and open public spaces; with open public spaces being the most common category (1,497 observations or 38.9%) \[[Supplementary Table 1](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#App1), Appendix\]. After excluding children aged \<2 years (29 observations) and children with special needs (one observation) for whom mask usage is not mandated, there were 3,821 observations that were analysed. Of these 3,821 observed individuals, 2,149 (56.2%) were female, 3,569 (93.4%) were adults (≥21 years), 212 (5.5%) were children estimated to be 6–20 years old and 40 (1.0%) were children estimated to be 2–5 years old. As no individual identifiers were collected, it is not known whether any individual was observed more than once at different locations or time points.
The overall proportion of full compliance with mask usage in the study was 79.7%, while that for poor compliance with mask usage and no usage of mask was 14.0% and 6.3%, respectively \[[Table 1](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-t001)\]. After correcting for instances of ‘allowable non-compliance’, the overall proportions of full compliance, poor compliance and no mask usage were 84.5%, 12.9% and 2.6%, respectively. Pitfalls in mask wearing included covering the mouth and nose but having large gaps above or below the mask (235/464, 50.7% of poor compliance observations), not covering the nose (*n* = 140, 30.2%), wearing the mask around the chin (*n* = 67, 14.4%), hanging the mask on the neck (*n* = 7, 1.5%) or dangling the mask on one ear (*n* = 9, 1.9%).
### Table 1.
Overall compliance to mask use by different age groupsa.
| Variable | *n* (%) | Total | | |
|---|---|---|---|---|
| Full complianceb | Poor compliancec | No maskd | | |
| Before excluding allowable reasons for mask non-compliancee | | | | |
| Adult (≥21 years) | 2,848 (79.8) | 505 (14.1) | 217 (6.1) | 3,569 |
| Child (6–20 years) | 177 (83.5) | 23 (10.8) | 11 (5.2) | 212 |
| Child (2–5 years) | 22 (55) | 6 (15) | 12 (30) | 40 |
| Total | 3,047 (79.7) | 534 (14.0) | 240 (6.3) | 3,821 |
| After excluding allowable reasons for mask non-compliancee | | | | |
| Adult (≥21 years) | 2,848 (84.5) | 440 (13.0) | 85 (2.5) | 3,372 |
| Child (6–20 years) | 177 (88.1) | 20 (10.0) | 3 (1.5) | 201 |
| Child (2–5 years) | 22 (66.7) | 4 (12.1) | 7 (21.2) | 33 |
| Total | 3,047 (84.5) | 464 (12.9) | 95 (2.6) | 3,606 |
aAge groups refers to estimated age. b‘Full compliance’ with mask usage was defined as using any one of the following type of face mask: fabric mask, surgical mask, face shield, a combination of face mask and face shield, or N95 mask, with the mask or shield fully covering the individual’s mouth and nose, upper boundary moulded over the nose with an appropriate fit and lower boundary below the chin. c‘Poor compliance’ with mask usage was defined as wearing a mask incorrectly (e.g. with either the mouth or nose exposed, the mask around the chin or neck, the upper or lower boundary is not fitted properly) or using an inappropriate mask (e.g. mask with valve). d‘No mask’ was defined as not wearing any facial covering at all. eAccording to the Singapore law, individuals are allowed to remove their mask for the following activities: eating or drinking, exercising or driving alone/with family members in the car
Male gender was associated with incorrect or absent mask use (adjusted odds ratio \[aOR\] 0.69, 95% confidence interval \[CI\] 0.56–0.85) \[[Table 2](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-t002)\]. Use of a surgical mask was associated with improved compliance (aOR 1.99, 95% CI 1.62–2.44) as compared to the use of a fabric mask. Full mask compliance was less frequently observed in spaces that were crowded (OR 0.77, 95% CI 0.64–0.93 in univariate analysis). A detailed analysis of venue categories found that mask compliance was lower in indoor F\&B establishments, healthcare facilities and retail and service venues compared to open public spaces, with a corrected compliance rate of 88.3% in open spaces but falling to 70.0% in indoor F\&B establishments \[[Figure 1](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-f001)\]. Instances of pitfalls in mask wearing in F\&B venues occurred while queueing, ordering food, waiting for food, talking, serving food or cleaning tables.
### Table 2.
Binary logistic regression analysis of factors associated with poor mask compliance or no mask usage.
| Variable | *n* (%) | Univariate analysis | Multivariate analysis | | | |
|---|---|---|---|---|---|---|
| Full compliance (*n*\=3,047) | Poor compliance or no mask use (*n*\=559) | OR (95% CI) for full compliance | *P* | OR ratio (95% CI) for full compliance | *P* | |
| Male gender | 1,269 (41.7) | 289 (51.7) | 0\.67 (0.56–0.80) | \<0.0001 | 0\.69 (0.56–0.85) | \<0.0001 |
| Age group | | | | 0\.007 | | |
| Adult (≥21 years) | 2,848 (93.5) | 524 (93.7) | Ref | Ref | Ref | Ref |
| Child (6–20 years) | 177 (5.8) | 24 (4.3) | 1\.36 (0.88–2.10) | 0\.17 | 1\.52 (0.93–2.49) | 0\.09 |
| Child (2–5 years) | 22 (0.7) | 11 (2.0) | 0\.37 (0.18–0.76) | 0\.007 | 0\.72 (0.24–2.16) | 0\.56 |
| Type of mask | | | | \<0.0001 | | |
| Fabric mask | 1,122 (36.9) | 246 (53.0) | Ref | Ref | Ref | Ref |
| Surgical mask | 1,907 (62.6) | 217 (46.8) | 1\.93 (1.58–2.35) | \<0.0001 | 1\.99 (1.62–2.44) | \<0.001 |
| Face shield | 0 | 1 (0.22) | NA | NA | NA | NA |
| N95 respirator | 4 (0.13) | 0 | NA | NA | NA | NA |
| Both mask and shield | 12 (0.39) | 0 | NA | NA | NA | NA |
| Securing method | | | | 0\.42 | | |
| Ear loop | 2,857 (94.0) | 444 (95.5) | Ref | Ref | Ref | Ref |
| Tied around head | 45 (1.5) | 6 (1.3) | 1\.17 (0.49–2.75) | 0\.73 | 1\.00 (0.42–2.39) | \>0.99 |
| Loop extender | 137 (4.5) | 15 (3.2) | 1\.42 (0.83–2.44) | 0\.21 | 1\.25 (0.72–2.19) | 0\.43 |
| Crowded venuea | 1,031 (33.8) | 223 (39.9) | 0\.77 (0.64–0.93) | 0\.006 | 0\.85 (0.67–1.06) | 0\.15 |
| Type of location | | | | \<0.0001 | | |
| Open public space | 1,258 (41.3) | 166 (29.7) | Ref | Ref | Ref | Ref |
| F\&B (indoor) | 266 (8.7) | 114 (20.4) | 0\.31 (0.23–0.40) | \<0.0001 | 0\.41 (0.29–0.59) | \<0.001 |
| F\&B (outdoor) | 134 (4.4) | 49 (8.8) | 0\.36 (0.25–0.52) | \<0.0001 | 0\.66 (0.40–1.10) | 0\.11 |
| Healthcare facility | 180 (5.9) | 41 (7.3) | 0\.58 (0.40–0.84) | 0\.004 | 0\.61 (0.39–0.94) | 0\.03 |
| Transportation | 672 (22.1) | 89 (15.9) | 1\.00 (0.76–1.31) | 0\.98 | 0\.85 (0.60–1.18) | 0\.33 |
| Retail and services | 537 (17.6) | 100 (17.9) | 0\.71 (0.54–0.93) | 0\.012 | 0\.57 (0.42–0.79) | 0\.001 |
| Type of activity | | | | \<0.0001 | | |
| Standing or sitting idly | 324 (10.8) | 91 (16.3) | Ref | Ref | Ref | Ref |
| Customer service | 206 (6.8) | 16 (2.9) | 3\.62 (2.07–6.33) | \<0.0001 | 3\.62 (1.95–6.75) | \<0.001 |
| Using electronic device | 334 (11.1) | 49 (8.8) | 1\.91 (1.31–2.80) | \<0.0001 | 2\.89 (1.80–4.62) | \<0.001 |
| Preparing food or beverage | 48 (1.6) | 10 (1.8) | 1\.35 (0.66–2.77) | 0\.42 | 1\.63 (0.71–3.72) | 0\.25 |
| Shopping | 412 (13.4) | 64 (11.5) | 1\.81 (1.27–2.57) | 0\.001 | 2\.38 (1.55–3.64) | \<0.001 |
| Smoking | 0 | 17 (3.0) | NA | NA | NA | NA |
| Using transportation service | 229 (7.6) | 23 (4.1) | 2\.80 (1.72–4.55) | \<0.0001 | 2\.19 (1.25–3.82) | 0\.006 |
| Talking | 617 (20.5) | 158 (28.3) | 1\.10 (0.82–1.47) | 0\.53 | 1\.31 (0.93–1.85) | 0\.12 |
| Walking | 843 (28.0) | 131 (23.4) | 1\.81 (1.34–2.43) | \<0.0001 | 1\.55 (1.10–2.19) | 0\.01 |
| Exempted activityb | 34 (1.1) | 0 | NA | NA | NA | NA |
*P* values were obtained using *χ*2 test for comparison across categorical variables, and binary logistic regression was used to obtain the individual OR of each variable. Hosmer–Lemeshow test was used for goodness-of-fit of multivariable model (*P* = 0.791). aCrowded venue was defined as an environment where safe distancing of 1 m between individuals is not possible due to the number of people in the venue. bExempted activity includes eating, drinking, exercising or driving, whereby mask use is neither mandated or practical. CI: confidence interval, F\&B: food and beverage establishment, NA: not applicable, OR: odds ratio, Ref: reference variable
### Figure 1.
Graph shows the proportion of individuals observed with full mask compliance (excluding instances of allowable non-compliance) by venue type. F\&B: food and beverage establishment (e.g. restaurant, hawker centre, food court).
An analysis of face or mask touching behaviour showed that a large proportion of individuals touched their mask (10.7%) or face (13.5%) during the observations \[[Table 3](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-t003)\]. The most common area of the face touched was the head (35.6%), followed by the mouth (21.4%) \[[Figure 2](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-f002)\]. Of significant concern is the small number of individuals who performed hand hygiene before (*n* = 2) and after (*n* = 3) touching their mask or face \[[Table 3](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-t003)\]. Only one individual performed hand hygiene both before and after as per the recommended infection control precautions.
### Table 3.
Frequency of mask or face touching behaviour and hand hygiene by age.
| Age groupa | *n* (%) | | | |
|---|---|---|---|---|
| Touched mask | Touched face | Hand hygiene beforeb | Hand hygiene afterb | |
| Adult (≥21 years) | 377 (10.6) | 466 (13.1) | 2 (0.28) | 3 (0.42) |
| Child (6–20 years) | 30 (14.2) | 38 (17.9) | 0 | 0 |
| Child (2–5 years) | 3 (7.5) | 10 (25) | 0 | 0 |
| Total | 410 (10.7) | 514 (13.5) | 2 (0.25) | 3 (0.38) |
aAge group refers to estimated age. bPercentage is expressed using the denominator of the number of individuals who touched either their mask or face.
### Figure 2.
Graph shows the frequency of different areas of the face touched during face-touching observations. Percentages are expressed using the denominator of the number of individuals who touched their face, with some observed to have touched more than one area. ‘Face’ refers to the areas of the face other than the mouth, nose, ears or eyes.
Being fully compliant with mask usage was associated with a lower rate of face or mask touching behaviour \[[Tables 3](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-t003) and [4](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#singaporemedj.SMJ-2021-010-t004)\]. Children were also more likely to touch their mask or face. The use of a surgical mask compared to a fabric mask was significantly associated with a lower rate of touching one’s face or mask (OR 0.84, 95% CI 0.71–0.99). No significant differences were identified between different methods of wearing a face mask (e.g. ear loops, tying behind one’s head or use of a dedicated loop extender). Being in a crowded area was associated with increased face or mask touching behaviour, similar to the effect on lowered mask compliance.
### Table 4.
Factors associated with mask or face touching behaviour.
| Variable | *n* (%) | Odds ratio (95% CI) | *P* | |
|---|---|---|---|---|
| Mask or face touching (*n*\=789) | No mask or face touching (*n*\=3,032) | | | |
| Male gender | 337 (42.7) | 1335 (44.0) | 0\.95 (0.81–1.11) | 0\.51 |
| Age groupa | | | | 0\.001 |
| Adult (≥21 years) | 714 (90.5) | 2855 (94.2) | Ref | Ref |
| Child (6–20 years) | 62 (7.9) | 150 (5.0) | 1\.65 (1.22–2.25) | 0\.001 |
| Child (2–5 years) | 13 (1.7) | 27 (0.9) | 1\.93 (0.99–3.75) | 0\.054 |
| Type of mask | | | | 0\.07 |
| Fabric mask | 296 (42.8) | 1106 (38.3) | Ref | Ref |
| Surgical mask | 396 (57.2) | 1763 (61.1) | 0\.84 (0.71–0.99) | 0\.04 |
| Face shield | 0 | 2 (0.07) | NA | NA |
| N95 respirator | 0 | 4 (0.14) | NA | NA |
| Both mask and shield | 0 | 12 (0.42) | NA | NA |
| Securing method | | | | 0\.52 |
| Ear loop | 660 (94.7) | 2704 (93.9) | Ref | Ref |
| Tied around head | 7 (1.0) | 45 (1.6) | 0\.64 (0.29–1.42) | 0\.27 |
| Loop extender | 30 (4.3) | 130 (4.5) | 0\.95 (0.63–1.42) | 0\.79 |
| Full mask compliance | 506 (64.1) | 2541 (83.8) | 0\.35 (0.29–0.41) | \<0.0001 |
| Crowded venueb | 311 (39.4) | 1044 (34.4) | 1\.24 (1.05–1.46) | 0\.009 |
*P* values were obtained using *χ*2 test for comparison across categorical variables, and binary logistic regression was used to obtain the individual odds ratio of each variable. aAge group refers to estimated age. bCrowded venue was defined as an environment where safe distancing of 1 m between individuals is not possible due to the number of people in the venue. CI: confidence interval, NA: not applicable, Ref: reference variable
## DISCUSSION
This study assessed the compliance rate and appropriate use of face masks by the general public across a broad range of public venues. The overall rate of mask compliance was high at 84.5%, which is higher than reported rates in other countries such as the United States, the United Kingdom and Australia.\[[17](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R17)\] This is likely largely due to strict legislation mandating mask usage in Singapore. Other contributing factors could include active enforcement by safe distancing ambassadors (designated public health officers who patrol public spaces to ensure compliance with public health measures) and high level of public trust in the Singapore government. Nonetheless, we identified several problem areas in mask usage and personal hygiene.
First, we identified key demographic groups that may benefit from improved targeted public health messaging (men for appropriate mask usage and children for face and mask touching behaviour). This finding of lower mask-wearing compliance rates among men is similar to the findings of Haischer and colleagues in a similar community mask audit study conducted in the United States.\[[18](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R18)\]
Second, we identified several venues (indoor F\&B establishments, healthcare facilities and retail and services) where mask usage is comparably lower, and these places will benefit from improved surveillance and/or reminders to improve compliance. The finding that more crowded areas are associated with decreased mask compliance and increased face and mask touching behaviour is concerning and unexpected, given that the transmission risk is expected to be the greatest in crowded areas.\[[19](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R19)\] We hypothesise that ventilation may be comparably poorer in crowded areas, resulting in more sweating and discomfort for mask users, and hence, higher rates of mask or face touching for mask adjustment, leading to poor compliance. An alternative explanation could be that in crowded indoor areas, people feel like they are less likely to be caught or policed for non-compliance, resulting in more lax behaviour. Systemic interventions should be considered to ensure that such situations are minimised, for example optimising ventilation and air-flow, imposing venue capacity limitations or increasing surveillance.\[[19](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R19)\]
Third, the finding of almost zero hand hygiene practised before and after face or mask touching is of concern and should be emphasised in future public health messaging. Avoidance of touching of one’s eyes, mouth and nose is advised to prevent the inoculation of SARS-CoV-2 by touch after contact with contaminated surfaces,\[[20](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R20)\] and thus hand hygiene before and after face or mask touching is an important instruction that should be disseminated. Theoretical concern has also been raised that the use of face masks would be associated with an increased incidence of users touching their face (e.g. to adjust the mask or to scratch their nose or mouth) as a result of the discomfort associated with mask wearing, resulting in a counterproductive effect. In contrast, a large international cross-sectional study by Chen *et al.*, which compared the observations of 2,887 individuals during the pandemic with 4,699 individuals before the pandemic, showed that mask usage was associated with reduced face-touching behaviour.\[[21](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R21)\] While we had no pre-pandemic data to compare the incidence of face-touching behaviour, in our study, we found that individuals who were fully compliant with mask usage had less face-touching behaviour compared to those who had poor compliance or did not use a mask, suggesting that face mask use was associated with reduced face-touching behaviour, though this association could be explained by an overall more conscientious attitude towards hygiene rather than direct causation. Of note, face-touching rates in our study were much higher than those reported by Chen *et al*. and comparable to their reported pre-pandemic rates (4.1%, 11.2% and 11.4% in China, South Korea and Europe, respectively).
The evidence for the optimal mask for use in healthcare settings remains inconclusive, with debate over whether a particulate respirator (e.g. filtering face piece \[FFP\]-2 or N95 respirator) is necessary in all healthcare settings.\[[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R2),[22](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R22)\] However, it is clear that widespread adoption of particulate respirators for the general public is not recommended, given the issues with resource limitations, requirement for fit testing and poor mask-wearing proficiency.\[[15](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R15)\] Public health messaging that N95 respirators are not required for general use was consistent, and we note that only four observations of N95 mask use were made.
Non-traditional or alternative materials for masks (such as cotton, silk or linen) have been evaluated in *in vitro* studies of filtration efficacy, and while they may be less effective than conventional surgical masks,\[[23](https://pmc.ncbi.nlm.nih.gov/articles/PMC11698284/#R23)\] they nonetheless proffer some degree of protection and may provide advantages in terms of comfort and availability. However, in this study, we observed that the use of fabric masks, as compared to surgical masks, is associated with poorer mask compliance and increased face or mask touching behaviour, and this is concerning and merits further evaluation. One possible explanation is that there were unmeasured confounding factors, and the demographics of fabric mask users could be different from that of surgical mask users (e.g. they could be less careful or informed, and hence paid less attention to infection control precautions).
Our study has several limitations. First, as it was only done in a single country, the findings may not necessarily be applicable to other settings, especially in countries where mask policy is not backed by law, or where other cultural or political influences affect the decision to use a mask. Second, we did not collect individually identifiable information or conduct detailed individual surveys, and hence could not further narrow down the demographic factors associated with mask compliance or evaluate the general public’s knowledge and attitudes towards mask use. For that same reason, the categorised age groups were only an estimate based on the child’s appearance and there may have been mis-classification in some instances. Furthermore, observations were conducted during daytime office hours only; hence, we did not explore the impact of time of day on mask-wearing behaviour. Third, while effort was made to ensure a good distribution of locations across the country, there was no systematic selection of sampling venues, and venues were instead selected on a best-effort basis by study team members based on proximity to the allocated MRT station. Nonetheless, the amount of bias this may have introduced should be minimal. Lastly, we did not conduct any statistical testing or external validation to assess if there was significant inter-observer variability among study team members; however, we assess that the amount of bias introduced by this factor to be very minimal.
In conclusion, compliance to mask usage was high during the COVID-19 pandemic in Singapore. However, we identified key problem areas to optimise future public health messaging, including high-risk venues where mask usage should be reinforced and the importance of hand hygiene before and after touching of one’s mask or face. Future studies can examine behavioural interventions at crowded areas to improve compliance. Similar community studies should be conducted in other settings to better inform and tailor public health policies.
### Conflicts of interest
Vasoo S is a member of the SMJ Editorial Board and was not involved in the publication decision of this article. The abovementioned funders played no role in the design and conduct of the study; the collection, management, analysis and interpretation of the data; the preparation, review or approval of the manuscript, and the decision to submit the manuscript for publication.
### Supplemental digital content
Appendix at <https://links.lww.com/SMJ/xx>
Supplementary Figure. 1
Spread of locations surveyed outlined on the Singapore map.
## APPENDIX
### Supplementary Table 1.
Breakdown of location types surveyed.
| Type of location | Number of observations | Percentage |
|---|---|---|
| F\&B (Indoor) | 493 | 12\.8 |
| F\&B (Outdoor) | 222 | 5\.8 |
| Healthcare Facilities | 225 | 5\.8 |
| Public Transport | 771 | 20\.0 |
| Public Spaces | 1497 | 38\.9 |
| Retail & Services | 643 | 16\.7 |
| **Total** | **3851** | 100 |
F\&B: food & beverage establishment (e.g. restaurant, hawker centre, food court)
## Funding Statement
This study was funded by the National Health Group–National Centre for Infectious Diseases COVID-19 Centre Grant (COVID19 CG0002). Ng OT is supported by the National Medical Research Council (NMRC) Clinician Scientist Award (MOH-000276). Marimuthu K is supported by the NMRC Clinician Scientist-Individual Research Grant (CIRG18Nov-0034).
## REFERENCES
- 1\.
Flaskerud JH. Masks, politics, culture and health. Issues Ment Health Nurs. 2020;41:846–9. doi: 10.1080/01612840.2020.1779883.
\[[DOI](https://doi.org/10.1080/01612840.2020.1779883)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32644832/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Issues%20Ment%20Health%20Nurs&title=Masks,%20politics,%20culture%20and%20health&author=JH%20Flaskerud&volume=41&publication_year=2020&pages=846-9&pmid=32644832&doi=10.1080/01612840.2020.1779883&)\]
- 2\.
Ong SWX, Coleman KK, Chia PY, Thoon KC, Pada S, Venkatachalam I, et al. Transmission modes of severe acute respiratory syndrome coronavirus 2 and implications on infection control: A review. Singapore Med J. 2022;63:61–7. doi: 10.11622/smedj.2020114.
\[[DOI](https://doi.org/10.11622/smedj.2020114)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC9251227/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32729311/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Singapore%20Med%20J&title=Transmission%20modes%20of%20severe%20acute%20respiratory%20syndrome%20coronavirus%202%20and%20implications%20on%20infection%20control:%20A%20review&author=SWX%20Ong&author=KK%20Coleman&author=PY%20Chia&author=KC%20Thoon&author=S%20Pada&volume=63&publication_year=2022&pages=61-7&pmid=32729311&doi=10.11622/smedj.2020114&)\]
- 3\.
Sommerstein R, Fux CA, Vuichard-Gysin D, Abbas M, Marschall J, Balmelli C, et al. Risk of SARS-CoV-2 transmission by aerosols, the rational use of masks, and protection of healthcare workers from COVID-19. Antimicrob Resist Infect Control. 2020;9:100. doi: 10.1186/s13756-020-00763-0.
\[[DOI](https://doi.org/10.1186/s13756-020-00763-0)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7336106/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32631450/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Antimicrob%20Resist%20Infect%20Control&title=Risk%20of%20SARS-CoV-2%20transmission%20by%20aerosols,%20the%20rational%20use%20of%20masks,%20and%20protection%20of%20healthcare%20workers%20from%20COVID-19&author=R%20Sommerstein&author=CA%20Fux&author=D%20Vuichard-Gysin&author=M%20Abbas&author=J%20Marschall&volume=9&publication_year=2020&pages=100&pmid=32631450&doi=10.1186/s13756-020-00763-0&)\]
- 4\.
Advice on the use of masks in the context of COVID-19: World Health Organization. 2020. \[Last accessed on 2020 Aug 18\]. \[Updated 2020 Jun 05\] Available from:<https://apps.who.int/iris/bitstream/handle/10665/332293/WHO-2019-nCov-IPC_Masks-2020.4-eng.pdf> .
- 5\.
Considerations for Wearing Masks: Centers for Disease Control and Prevention. 2020. \[Last accessed on 2020 Aug 18\]. \[Updated 2020 Aug 07\] Available from:<https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html> .
- 6\.
Wei WE, Li Z, Chiew CJ, Yong SE, Toh MP, Lee VJ. Presymptomatic transmission of SARS-CoV-2-Singapore, January 23-March 16, 2020. MMWR Morb Mortal Wkly Rep. 2020;69:411–5. doi: 10.15585/mmwr.mm6914e1.
\[[DOI](https://doi.org/10.15585/mmwr.mm6914e1)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7147908/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32271722/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=MMWR%20Morb%20Mortal%20Wkly%20Rep&title=Presymptomatic%20transmission%20of%20SARS-CoV-2-Singapore,%20January%2023-March%2016,%202020&author=WE%20Wei&author=Z%20Li&author=CJ%20Chiew&author=SE%20Yong&author=MP%20Toh&volume=69&publication_year=2020&pages=411-5&pmid=32271722&doi=10.15585/mmwr.mm6914e1&)\]
- 7\.
Furukawa NW, Brooks JT, Sobel J. Evidence supporting transmission of severe acute respiratory syndrome coronavirus 2 while presymptomatic or asymptomatic. Emerg Infect Dis. 2020;26:e201595. doi: 10.3201/eid2607.201595.
\[[DOI](https://doi.org/10.3201/eid2607.201595)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7323549/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32364890/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Emerg%20Infect%20Dis&title=Evidence%20supporting%20transmission%20of%20severe%20acute%20respiratory%20syndrome%20coronavirus%202%20while%20presymptomatic%20or%20asymptomatic&author=NW%20Furukawa&author=JT%20Brooks&author=J%20Sobel&volume=26&publication_year=2020&pages=e201595&pmid=32364890&doi=10.3201/eid2607.201595&)\]
- 8\.
Eikenberry SE, Mancuso M, Iboi E, Phan T, Eikenberry K, Kuang Y, et al. To mask or not to mask: Modeling the potential for face mask use by the general public to curtail the COVID-19 pandemic. Infect Dis Model. 2020;5:293–308. doi: 10.1016/j.idm.2020.04.001.
\[[DOI](https://doi.org/10.1016/j.idm.2020.04.001)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7186508/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32355904/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Infect%20Dis%20Model&title=To%20mask%20or%20not%20to%20mask:%20Modeling%20the%20potential%20for%20face%20mask%20use%20by%20the%20general%20public%20to%20curtail%20the%20COVID-19%20pandemic&author=SE%20Eikenberry&author=M%20Mancuso&author=E%20Iboi&author=T%20Phan&author=K%20Eikenberry&volume=5&publication_year=2020&pages=293-308&pmid=32355904&doi=10.1016/j.idm.2020.04.001&)\]
- 9\.
Worby CJ, Chang HH. Face mask use in the general population and optimal resource allocation during the COVID-19 pandemic. Nat Commun. 2020;11:4049. doi: 10.1038/s41467-020-17922-x.
\[[DOI](https://doi.org/10.1038/s41467-020-17922-x)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7426871/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32792562/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Nat%20Commun&title=Face%20mask%20use%20in%20the%20general%20population%20and%20optimal%20resource%20allocation%20during%20the%20COVID-19%20pandemic&author=CJ%20Worby&author=HH%20Chang&volume=11&publication_year=2020&pages=4049&pmid=32792562&doi=10.1038/s41467-020-17922-x&)\]
- 10\.
Schwartz KL, Murti M, Finkelstein M, Leis JA, Fitzgerald-Husek A, Bourns L, et al. Lack of COVID-19 transmission on an international flight. CMAJ. 2020;192:E410. doi: 10.1503/cmaj.75015.
\[[DOI](https://doi.org/10.1503/cmaj.75015)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7162437/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32392504/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=CMAJ&title=Lack%20of%20COVID-19%20transmission%20on%20an%20international%20flight&author=KL%20Schwartz&author=M%20Murti&author=M%20Finkelstein&author=JA%20Leis&author=A%20Fitzgerald-Husek&volume=192&publication_year=2020&pages=E410&pmid=32392504&doi=10.1503/cmaj.75015&)\]
- 11\.
Hendrix MJ, Walde C, Findley K, Trotman R. Absence of apparent transmission of SARS-CoV-2 from two stylists after exposure at a hair salon with a Universal Face Covering Policy —Springfield, Missouri, May 2020. MMWR Morb Mortal Wkly Rep. 2020;69:930–2. doi: 10.15585/mmwr.mm6928e2.
\[[DOI](https://doi.org/10.15585/mmwr.mm6928e2)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32673300/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=MMWR%20Morb%20Mortal%20Wkly%20Rep&title=Absence%20of%20apparent%20transmission%20of%20SARS-CoV-2%20from%20two%20stylists%20after%20exposure%20at%20a%20hair%20salon%20with%20a%20Universal%20Face%20Covering%20Policy%20%E2%80%94Springfield,%20Missouri,%20May%202020&author=MJ%20Hendrix&author=C%20Walde&author=K%20Findley&author=R%20Trotman&volume=69&publication_year=2020&pages=930-2&pmid=32673300&doi=10.15585/mmwr.mm6928e2&)\]
- 12\.
Cheng VC, Wong SC, Chuang VW, So SY, Chen JH, Sridhar S, et al. The role of community-wide wearing of face mask for control of coronavirus disease 2019 (COVID-19) epidemic due to SARS-CoV-2. J Infect. 2020;81:107–14. doi: 10.1016/j.jinf.2020.04.024.
\[[DOI](https://doi.org/10.1016/j.jinf.2020.04.024)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7177146/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32335167/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=J%20Infect&title=The%20role%20of%20community-wide%20wearing%20of%20face%20mask%20for%20control%20of%20coronavirus%20disease%202019%20\(COVID-19\)%20epidemic%20due%20to%20SARS-CoV-2&author=VC%20Cheng&author=SC%20Wong&author=VW%20Chuang&author=SY%20So&author=JH%20Chen&volume=81&publication_year=2020&pages=107-14&pmid=32335167&doi=10.1016/j.jinf.2020.04.024&)\]
- 13\.
Guallar MP, Meirino R, Donat-Vargas C, Corral O, Jouve N, Soriano V. Inoculum at the time of SARS-CoV-2 exposure and risk of disease severity. Int J Infect Dis. 2020;97:290–2. doi: 10.1016/j.ijid.2020.06.035.
\[[DOI](https://doi.org/10.1016/j.ijid.2020.06.035)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7293836/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32553720/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Int%20J%20Infect%20Dis&title=Inoculum%20at%20the%20time%20of%20SARS-CoV-2%20exposure%20and%20risk%20of%20disease%20severity&author=MP%20Guallar&author=R%20Meirino&author=C%20Donat-Vargas&author=O%20Corral&author=N%20Jouve&volume=97&publication_year=2020&pages=290-2&pmid=32553720&doi=10.1016/j.ijid.2020.06.035&)\]
- 14\.
Gandhi M, Beyrer C, Goosby E. Masks do more than protect others during covid-19: Reducing the inoculum of SARS-CoV-2 to protect the wearer. J Gen Intern Med. 2020;35:3063–6. doi: 10.1007/s11606-020-06067-8.
\[[DOI](https://doi.org/10.1007/s11606-020-06067-8)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7393808/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32737790/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=J%20Gen%20Intern%20Med&title=Masks%20do%20more%20than%20protect%20others%20during%20covid-19:%20Reducing%20the%20inoculum%20of%20SARS-CoV-2%20to%20protect%20the%20wearer&author=M%20Gandhi&author=C%20Beyrer&author=E%20Goosby&volume=35&publication_year=2020&pages=3063-6&pmid=32737790&doi=10.1007/s11606-020-06067-8&)\]
- 15\.
Yeung W, Ng K, Fong JMN, Sng J, Tai BC, Chia SE. Assessment of proficiency of n95 mask donning among the general public in Singapore. JAMA Netw Open. 2020;3:e209670. doi: 10.1001/jamanetworkopen.2020.9670.
\[[DOI](https://doi.org/10.1001/jamanetworkopen.2020.9670)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7240349/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32432708/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=JAMA%20Netw%20Open&title=Assessment%20of%20proficiency%20of%20n95%20mask%20donning%20among%20the%20general%20public%20in%20Singapore&author=W%20Yeung&author=K%20Ng&author=JMN%20Fong&author=J%20Sng&author=BC%20Tai&volume=3&publication_year=2020&pages=e209670&pmid=32432708&doi=10.1001/jamanetworkopen.2020.9670&)\]
- 16\.
Guidance for use of masks and face shields: Ministry of Health. Singapore: 2020. \[Last accessed on 2020 Aug 18\]. Available from:<https://www.moh.gov.sg/news-highlights/details/guidance-for-use-of-masks-and-face-shields> .
\[[Google Scholar](https://scholar.google.com/scholar_lookup?title=Guidance%20for%20use%20of%20masks%20and%20face%20shields:%20Ministry%20of%20Health&publication_year=2020&)\]
- 17\.
MacIntyre CR, Nguyen PY, Chughtai AA, Trent M, Gerber B, Steinhofel K, et al. Mask use, risk-mitigation behaviours and pandemic fatigue during the COVID-19 pandemic in five cities in Australia, the UK and USA: A cross-sectional survey. Int J Infect Dis. 2021;106:199–207. doi: 10.1016/j.ijid.2021.03.056.
\[[DOI](https://doi.org/10.1016/j.ijid.2021.03.056)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7985682/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/33771668/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Int%20J%20Infect%20Dis&title=Mask%20use,%20risk-mitigation%20behaviours%20and%20pandemic%20fatigue%20during%20the%20COVID-19%20pandemic%20in%20five%20cities%20in%20Australia,%20the%20UK%20and%20USA:%20A%20cross-sectional%20survey&author=CR%20MacIntyre&author=PY%20Nguyen&author=AA%20Chughtai&author=M%20Trent&author=B%20Gerber&volume=106&publication_year=2021&pages=199-207&pmid=33771668&doi=10.1016/j.ijid.2021.03.056&)\]
- 18\.
Haischer MH, Beilfuss R, Hart MR, Opielinski L, Wrucke D, Zirgaitis G, et al. Who is wearing a mask?Gender-, age-, and location-related differences during the COVID-19 pandemic. PLoS One. 2020;15:e0240785. doi: 10.1371/journal.pone.0240785.
\[[DOI](https://doi.org/10.1371/journal.pone.0240785)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7561164/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/33057375/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=PLoS%20One&title=Who%20is%20wearing%20a%20mask?Gender-,%20age-,%20and%20location-related%20differences%20during%20the%20COVID-19%20pandemic&author=MH%20Haischer&author=R%20Beilfuss&author=MR%20Hart&author=L%20Opielinski&author=D%20Wrucke&volume=15&publication_year=2020&pages=e0240785&pmid=33057375&doi=10.1371/journal.pone.0240785&)\]
- 19\.
Morawska L, Tang JW, Bahnfleth W, Bluyssen PM, Boerstra A, Buonanno G, et al. How can airborne transmission of COVID-19 indoors be minimised? Environ Int. 2020;142:105832. doi: 10.1016/j.envint.2020.105832.
\[[DOI](https://doi.org/10.1016/j.envint.2020.105832)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7250761/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32521345/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Environ%20Int&title=How%20can%20airborne%20transmission%20of%20COVID-19%20indoors%20be%20minimised?&author=L%20Morawska&author=JW%20Tang&author=W%20Bahnfleth&author=PM%20Bluyssen&author=A%20Boerstra&volume=142&publication_year=2020&pages=105832&pmid=32521345&doi=10.1016/j.envint.2020.105832&)\]
- 20\.
Coronavirus disease (COVID-19) advice for the public: World Health Organization. 2020. \[Last accessed on 2020 Aug 18\]. Available from:<https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public> .
- 21\.
Chen YJ, Qin G, Chen J, Xu JL, Feng DY, Wu XY, et al. Comparison of face-touching behaviors before and during the coronavirus disease 2019 pandemic. JAMA Netw Open. 2020;3:e2016924. doi: 10.1001/jamanetworkopen.2020.16924.
\[[DOI](https://doi.org/10.1001/jamanetworkopen.2020.16924)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC12124488/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32725247/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=JAMA%20Netw%20Open&title=Comparison%20of%20face-touching%20behaviors%20before%20and%20during%20the%20coronavirus%20disease%202019%20pandemic&author=YJ%20Chen&author=G%20Qin&author=J%20Chen&author=JL%20Xu&author=DY%20Feng&volume=3&publication_year=2020&pages=e2016924&pmid=32725247&doi=10.1001/jamanetworkopen.2020.16924&)\]
- 22\.
Conly J, Seto WH, Pittet D, Holmes A, Chu M, Hunter PR, et al. Use of medical face masks versus particulate respirators as a component of personal protective equipment for health care workers in the context of the COVID-19 pandemic. Antimicrob Resist Infect Control. 2020;9:126. doi: 10.1186/s13756-020-00779-6.
\[[DOI](https://doi.org/10.1186/s13756-020-00779-6)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7406874/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32762735/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=Antimicrob%20Resist%20Infect%20Control&title=Use%20of%20medical%20face%20masks%20versus%20particulate%20respirators%20as%20a%20component%20of%20personal%20protective%20equipment%20for%20health%20care%20workers%20in%20the%20context%20of%20the%20COVID-19%20pandemic&author=J%20Conly&author=WH%20Seto&author=D%20Pittet&author=A%20Holmes&author=M%20Chu&volume=9&publication_year=2020&pages=126&pmid=32762735&doi=10.1186/s13756-020-00779-6&)\]
- 23\.
Wilson AM, Abney SE, King MF, Weir MH, Lopez-Garcia M, Sexton JD, et al. COVID-19 and use of non-traditional masks: How do various materials compare in reducing the risk of infection for mask wearers? J Hosp Infect. 2020;105:640–2. doi: 10.1016/j.jhin.2020.05.036.
\[[DOI](https://doi.org/10.1016/j.jhin.2020.05.036)\] \[[PMC free article](https://pmc.ncbi.nlm.nih.gov/articles/PMC7264937/)\] \[[PubMed](https://pubmed.ncbi.nlm.nih.gov/32502581/)\] \[[Google Scholar](https://scholar.google.com/scholar_lookup?journal=J%20Hosp%20Infect&title=COVID-19%20and%20use%20of%20non-traditional%20masks:%20How%20do%20various%20materials%20compare%20in%20reducing%20the%20risk%20of%20infection%20for%20mask%20wearers?&author=AM%20Wilson&author=SE%20Abney&author=MF%20King&author=MH%20Weir&author=M%20Lopez-Garcia&volume=105&publication_year=2020&pages=640-2&pmid=32502581&doi=10.1016/j.jhin.2020.05.036&)\]
## Associated Data
*This section collects any data citations, data availability statements, or supplementary materials included in this article.*
### Supplementary Materials
Supplementary Figure. 1
Spread of locations surveyed outlined on the Singapore map. |
| Shard | 129 (laksa) |
| Root Hash | 7295144728021232729 |
| Unparsed URL | gov,nih!nlm,ncbi,pmc,/articles/PMC11698284/ s443 |