ℹ️ Skipped - page is already crawled
| Filter | Status | Condition | Details |
|---|---|---|---|
| HTTP status | PASS | download_http_code = 200 | HTTP 200 |
| Age cutoff | FAIL | download_stamp > now() - 6 MONTH | 6.6 months ago |
| History drop | PASS | isNull(history_drop_reason) | No drop reason |
| Spam/ban | PASS | fh_dont_index != 1 AND ml_spam_score = 0 | ml_spam_score=0 |
| Canonical | PASS | meta_canonical IS NULL OR = '' OR = src_unparsed | Not set |
| Property | Value |
|---|---|
| URL | https://www.cidrap.umn.edu/no-anaphylaxis-after-second-dose-mrna-covid-vaccine-study-finds |
| Last Crawled | 2025-10-03 20:19:10 (6 months ago) |
| First Indexed | 2022-12-19 01:15:20 (3 years ago) |
| HTTP Status Code | 200 |
| Meta Title | No anaphylaxis after second dose of mRNA COVID vaccine, study finds | CIDRAP |
| Meta Description | null |
| Meta Canonical | null |
| Boilerpipe Text | People who had a severe allergic reaction to their first dose of mRNA COVID-19 vaccine had no issues after their second dose, according to a retrospective multicenter US study today in JAMA Internal Medicine . Allergic reactions are estimated to occur in up to 2% of people after their first mRNA COVID-19 vaccine dose, with anaphylaxis reported in as many as 2.5 per 10,000 vaccinees. Anaphylaxis is a severe and potentially deadly systemic allergic reaction. From Jan 1 to Mar 31, a team led by researchers at Massachusetts General Hospital (MGH) analyzed data from 189 people who had sought care for allergic reactions within 4 hours after their first dose of the Pfizer/BioNTech or Moderna mRNA COVID-19. 20% have mild reactions to second dose The most common first-dose allergic reactions were flushing or redness (28%), dizziness (26%), tingling (24%), throat tightness (22%), hives (21%), and shortness of breath or wheezing (21%). Thirty-two patients (17%) experienced anaphylaxis. Of the patients with first-dose reactions, 130 (69%) were to the Moderna vaccine, and 59 (31%) were to Pfizer. Of the 189 total patients, 159 (84%) received a second dose of mRNA vaccine, 30% of whom were given antihistamines before their shot. All 159 patients, including 19 who had experienced anaphylaxis after the first dose, tolerated the second dose without severe complications. Immediate, potentially allergic reactions that occurred in 32 (20%) of patients resolved on their own or with antihistamine treatment. Median patient age was 43 years, and 86% were women. The authors said that the results demonstrate that a second dose of the Pfizer or Moderna COVID-19 vaccine is safe for those who had an allergic reaction to the first dose. "Although mild symptoms were reported in 20% of patients with second dose administration, all patients who received a second dose safely completed their vaccination series and could use mRNA COVID-19 vaccines in the future when indicated," they wrote. May not be classic allergic reactions Earlier this year, the Centers for Disease Control and Prevention announced that people who had an allergic reaction to a first dose of an mRNA vaccine should not get a second, recommending that they instead could follow up with the Johnson & Johnson single-dose COVID-19 vaccine. However, the study authors said their results suggest this "largely unstudied" strategy might not be needed. In fact, the researchers pointed out that the immediate second-dose mRNA vaccine reactions might not be classic allergic reactions at all because re-exposure to the same substance in classic allergy situations causes the same or worse symptoms. "Second dose tolerance following reactions to the first dose argues that either many of these initial reactions are not all truly allergic reactions, or supports an allergic, but non–immunoglobulin E–mediated mechanism in which symptoms can typically be abated with premedications," the researchers wrote. Co-senior author Aleena Banerji, MD, of MGH said in a hospital news release that it is important for people with a first-dose allergic reaction to complete the vaccine series, if possible. "After first dose reactions, allergy specialists may be useful to help guide risk/benefit assessments and assist with completion of safe vaccination," she said. |
| Markdown | Menu
- [News](https://www.cidrap.umn.edu/)
- [Topics & ProjectsToggle submenu](https://www.cidrap.umn.edu/no-anaphylaxis-after-second-dose-mrna-covid-vaccine-study-finds#mm-2)
- [Antimicrobial Resistance](https://www.cidrap.umn.edu/antimicrobial-stewardship)
- [COVID-19](https://www.cidrap.umn.edu/covid-19)
- [Chronic Wasting Disease](https://www.cidrap.umn.edu/chronic-wasting-disease)
- [Influenza](https://www.cidrap.umn.edu/influenza-general)
- [Resilient Drug Supply](https://www.cidrap.umn.edu/resilient-drug-supply)
- [Coronavirus Vaccines Roadmap](https://www.cidrap.umn.edu/coronavirus-vaccines-roadmap)
- [Influenza Vaccines Roadmap](https://ivr.cidrap.umn.edu/ "(opens in a new window)")
- [Roadmaps for Priority Pathogens](https://www.cidrap.umn.edu/roadmap-development)
- [Vaccine Integrity Project](https://www.cidrap.umn.edu/vaccine-integrity-project)
- [CIDRAP Leadership Forum](https://www.cidrap.umn.edu/forum "CIDRAP Leadership Forum")
- .
- .
- [All Topics A-Z](https://www.cidrap.umn.edu/infectious-disease-topics)
- [PodcastsToggle submenu](https://www.cidrap.umn.edu/no-anaphylaxis-after-second-dose-mrna-covid-vaccine-study-finds#mm-3)
- [Antimicrobial Stewardship](https://www.cidrap.umn.edu/antimicrobial-stewardship/superbugs-you)
- [Chronic Wasting Disease](https://www.cidrap.umn.edu/chronic-wasting-disease/cwd-pod)
- [Osterholm Update](https://www.cidrap.umn.edu/osterholm-update)
- [Newsletters](https://www.cidrap.umn.edu/newsletter)
- [AboutToggle submenu](https://www.cidrap.umn.edu/no-anaphylaxis-after-second-dose-mrna-covid-vaccine-study-finds#mm-4)
- [About CIDRAP](https://www.cidrap.umn.edu/about-cidrap)
- [CIDRAP in the News](https://www.cidrap.umn.edu/cidrap-news)
- [Our Staff](https://www.cidrap.umn.edu/about-us/cidrap-staff)
- [Our Director](https://www.cidrap.umn.edu/michael-t-osterholdm-phd-mph)
- [Osterholm in the Press](https://www.cidrap.umn.edu/osterholm-quotes)
- [Shop Merchandise](https://www.mnalumnimarket.com/collections/cidrap?utm_source=website&utm_medium=website&utm_campaign=CIDRAPdonate&utm_content=CIDRAP "(opens in a new window)")
- [Contact Us](https://www.cidrap.umn.edu/contact-us)
- [Donate](https://www.cidrap.umn.edu/support)
[Skip to main content](https://www.cidrap.umn.edu/no-anaphylaxis-after-second-dose-mrna-covid-vaccine-study-finds#main-content)
[Main navigation](https://www.cidrap.umn.edu/no-anaphylaxis-after-second-dose-mrna-covid-vaccine-study-finds#main-nav)
**University of Minnesota**
http://twin-cities.umn.edu/
612-625-5000
[Go to the U of M home page](http://twin-cities.umn.edu/ "(opens in a new window)")
[](https://www.cidrap.umn.edu/ "Home")
## Main navigation
- [News](https://www.cidrap.umn.edu/)
- - [Antimicrobial Resistance](https://www.cidrap.umn.edu/antimicrobial-stewardship)
- [COVID-19](https://www.cidrap.umn.edu/covid-19)
- [Chronic Wasting Disease](https://www.cidrap.umn.edu/chronic-wasting-disease)
- [Influenza](https://www.cidrap.umn.edu/influenza-general)
- [Resilient Drug Supply](https://www.cidrap.umn.edu/resilient-drug-supply)
- [All Topics A-Z](https://www.cidrap.umn.edu/infectious-disease-topics)
- [Coronavirus Vaccines Roadmap](https://www.cidrap.umn.edu/coronavirus-vaccines-roadmap)
- [Influenza Vaccines Roadmap](https://ivr.cidrap.umn.edu/ "(opens in a new window)")
- [Roadmaps for Priority Pathogens](https://www.cidrap.umn.edu/roadmap-development)
- [Vaccine Integrity Project](https://www.cidrap.umn.edu/vaccine-integrity-project)
- [CIDRAP Leadership Forum](https://www.cidrap.umn.edu/forum "CIDRAP Leadership Forum")
- .
- .
Topics & Projects
- - [Antimicrobial Stewardship](https://www.cidrap.umn.edu/antimicrobial-stewardship/superbugs-you)
- [Chronic Wasting Disease](https://www.cidrap.umn.edu/chronic-wasting-disease/cwd-pod)
- [Osterholm Update](https://www.cidrap.umn.edu/osterholm-update)
Podcasts
- [Newsletters](https://www.cidrap.umn.edu/newsletter)
- - [About CIDRAP](https://www.cidrap.umn.edu/about-cidrap)
- [CIDRAP in the News](https://www.cidrap.umn.edu/cidrap-news)
- [Our Staff](https://www.cidrap.umn.edu/about-us/cidrap-staff)
- [Our Director](https://www.cidrap.umn.edu/michael-t-osterholdm-phd-mph)
- [Osterholm in the Press](https://www.cidrap.umn.edu/osterholm-quotes)
- [Shop Merchandise](https://www.mnalumnimarket.com/collections/cidrap?utm_source=website&utm_medium=website&utm_campaign=CIDRAPdonate&utm_content=CIDRAP "(opens in a new window)")
- [Contact Us](https://www.cidrap.umn.edu/contact-us)
About
Search
- [Support](https://www.cidrap.umn.edu/support)
[Menu](https://www.cidrap.umn.edu/no-anaphylaxis-after-second-dose-mrna-covid-vaccine-study-finds#off-canvas "Menu")
# No anaphylaxis after second dose of mRNA COVID vaccine, study finds
Mary Van Beusekom \| News Writer \| CIDRAP News
July 26, 2021
[COVID-19](https://www.cidrap.umn.edu/covid-19)


> Mecklenburg County / Flickr cc
Share
People who had a severe allergic reaction to their first dose of mRNA COVID-19 vaccine had no issues after their second dose, according to a retrospective multicenter US [study](https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2782348?guestAccessKey=5bce44d8-672d-454c-bf71-b4b9a66cb866&utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_content=tfl&utm_term=072621 "(opens in a new window)") today in *JAMA Internal Medicine*.
Allergic reactions are estimated to occur in up to 2% of people after their first mRNA COVID-19 vaccine dose, with anaphylaxis reported in as many as 2.5 per 10,000 vaccinees. Anaphylaxis is a severe and potentially deadly systemic allergic reaction.
From Jan 1 to Mar 31, a team led by researchers at Massachusetts General Hospital (MGH) analyzed data from 189 people who had sought care for allergic reactions within 4 hours after their first dose of the Pfizer/BioNTech or Moderna mRNA COVID-19.
### 20% have mild reactions to second dose
The most common first-dose allergic reactions were flushing or redness (28%), dizziness (26%), tingling (24%), throat tightness (22%), hives (21%), and shortness of breath or wheezing (21%). Thirty-two patients (17%) experienced anaphylaxis. Of the patients with first-dose reactions, 130 (69%) were to the Moderna vaccine, and 59 (31%) were to Pfizer.
Of the 189 total patients, 159 (84%) received a second dose of mRNA vaccine, 30% of whom were given antihistamines before their shot. All 159 patients, including 19 who had experienced anaphylaxis after the first dose, tolerated the second dose without severe complications. Immediate, potentially allergic reactions that occurred in 32 (20%) of patients resolved on their own or with antihistamine treatment. Median patient age was 43 years, and 86% were women.
The authors said that the results demonstrate that a second dose of the Pfizer or Moderna COVID-19 vaccine is safe for those who had an allergic reaction to the first dose. "Although mild symptoms were reported in 20% of patients with second dose administration, all patients who received a second dose safely completed their vaccination series and could use mRNA COVID-19 vaccines in the future when indicated," they wrote.
### May not be classic allergic reactions
Earlier this year, the Centers for Disease Control and Prevention [announced](https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/allergic-reaction.html "(opens in a new window)") that people who had an allergic reaction to a first dose of an mRNA vaccine should not get a second, recommending that they instead could follow up with the Johnson & Johnson single-dose COVID-19 vaccine. However, the study authors said their results suggest this "largely unstudied" strategy might not be needed.
In fact, the researchers pointed out that the immediate second-dose mRNA vaccine reactions might not be classic allergic reactions at all because re-exposure to the same substance in classic allergy situations causes the same or worse symptoms.
"Second dose tolerance following reactions to the first dose argues that either many of these initial reactions are not all truly allergic reactions, or supports an allergic, but non–immunoglobulin E–mediated mechanism in which symptoms can typically be abated with premedications," the researchers wrote.
Co-senior author Aleena Banerji, MD, of MGH said in a hospital [news release](https://www.eurekalert.org/pub_releases/2021-07/mgh-scm072321.php "(opens in a new window)") that it is important for people with a first-dose allergic reaction to complete the vaccine series, if possible. "After first dose reactions, allergy specialists may be useful to help guide risk/benefit assessments and assist with completion of safe vaccination," she said.
## Related news
Previous
Next
[Infectious disease specialists lament 'chaos' of recent ACIP meeting September 23, 2025 Chris Dall ](https://www.cidrap.umn.edu/adult-non-flu-vaccines/infectious-disease-specialists-lament-chaos-recent-acip-meeting)
[CDC advisers weaken COVID vaccine recommendations but stop short of requiring prescriptions September 19, 2025 Lisa Schnirring ](https://www.cidrap.umn.edu/covid-19/cdc-advisers-weaken-covid-vaccine-recommendations-stop-short-requiring-prescriptions)
[Report: Cardiac risks must be considered when treating COVID-19 September 18, 2025 Stephanie Soucheray ](https://www.cidrap.umn.edu/covid-19/report-cardiac-risks-must-be-considered-when-treating-covid-19)
[Trial: Paxlovid retreatment after COVID rebound tied to faster drop in viral RNA but no clinical benefit October 2, 2025 Mary Van Beusekom ](https://www.cidrap.umn.edu/covid-19/trial-paxlovid-retreatment-after-covid-rebound-tied-faster-drop-viral-rna-no-clinical)
[COVID vaccines may have averted thousands of hospital stays in infants, pregnant women over 18 months September 30, 2025 Mary Van Beusekom ](https://www.cidrap.umn.edu/covid-19/covid-vaccines-may-have-averted-thousands-hospital-stays-infants-pregnant-women-over-18)
[Viewpoint: What we don’t see about vaccines COULD hurt us September 30, 2025 Vaccine Integrity Project Staff and Advisors ](https://www.cidrap.umn.edu/childhood-vaccines/viewpoint-what-we-don-t-see-about-vaccines-could-hurt-us)
[Inhaled heparin slashes ventilation, death in COVID patients, analysis suggests September 29, 2025 Mary Van Beusekom ](https://www.cidrap.umn.edu/covid-19/inhaled-heparin-slashes-ventilation-death-covid-patients-analysis-suggests)
[Nearly 7 in 10 COVID survivors tested didn't know they had a dulled sense of smell September 26, 2025 Mary Van Beusekom ](https://www.cidrap.umn.edu/covid-19/nearly-7-10-covid-survivors-tested-didnt-know-they-had-dulled-sense-smell)
[Infectious disease specialists lament 'chaos' of recent ACIP meeting September 23, 2025 Chris Dall ](https://www.cidrap.umn.edu/adult-non-flu-vaccines/infectious-disease-specialists-lament-chaos-recent-acip-meeting)
[CDC advisers weaken COVID vaccine recommendations but stop short of requiring prescriptions September 19, 2025 Lisa Schnirring ](https://www.cidrap.umn.edu/covid-19/cdc-advisers-weaken-covid-vaccine-recommendations-stop-short-requiring-prescriptions)
[Report: Cardiac risks must be considered when treating COVID-19 September 18, 2025 Stephanie Soucheray ](https://www.cidrap.umn.edu/covid-19/report-cardiac-risks-must-be-considered-when-treating-covid-19)
[Trial: Paxlovid retreatment after COVID rebound tied to faster drop in viral RNA but no clinical benefit October 2, 2025 Mary Van Beusekom ](https://www.cidrap.umn.edu/covid-19/trial-paxlovid-retreatment-after-covid-rebound-tied-faster-drop-viral-rna-no-clinical)
[COVID vaccines may have averted thousands of hospital stays in infants, pregnant women over 18 months September 30, 2025 Mary Van Beusekom ](https://www.cidrap.umn.edu/covid-19/covid-vaccines-may-have-averted-thousands-hospital-stays-infants-pregnant-women-over-18)
[Viewpoint: What we don’t see about vaccines COULD hurt us September 30, 2025 Vaccine Integrity Project Staff and Advisors ](https://www.cidrap.umn.edu/childhood-vaccines/viewpoint-what-we-don-t-see-about-vaccines-could-hurt-us)
[Inhaled heparin slashes ventilation, death in COVID patients, analysis suggests September 29, 2025 Mary Van Beusekom ](https://www.cidrap.umn.edu/covid-19/inhaled-heparin-slashes-ventilation-death-covid-patients-analysis-suggests)
[Nearly 7 in 10 COVID survivors tested didn't know they had a dulled sense of smell September 26, 2025 Mary Van Beusekom ](https://www.cidrap.umn.edu/covid-19/nearly-7-10-covid-survivors-tested-didnt-know-they-had-dulled-sense-smell)
[Infectious disease specialists lament 'chaos' of recent ACIP meeting September 23, 2025 Chris Dall ](https://www.cidrap.umn.edu/adult-non-flu-vaccines/infectious-disease-specialists-lament-chaos-recent-acip-meeting)
[CDC advisers weaken COVID vaccine recommendations but stop short of requiring prescriptions September 19, 2025 Lisa Schnirring ](https://www.cidrap.umn.edu/covid-19/cdc-advisers-weaken-covid-vaccine-recommendations-stop-short-requiring-prescriptions)
[Report: Cardiac risks must be considered when treating COVID-19 September 18, 2025 Stephanie Soucheray ](https://www.cidrap.umn.edu/covid-19/report-cardiac-risks-must-be-considered-when-treating-covid-19)
## This week's top reads
1. [Multistate Listeria outbreak tied to packaged meals expands Twenty people in 15 states have been now sickened in the outbreak, and 4 have died. Chris Dall September 29, 2025](https://www.cidrap.umn.edu/foodborne-disease/multistate-listeria-outbreak-tied-packaged-meals-expands)
2. [Experts push back on Trump's tying autism to childhood vaccines, Tylenol The announcements were not based on any new evidence or research. Stephanie Soucheray September 23, 2025 ](https://www.cidrap.umn.edu/public-health/experts-push-back-trumps-tying-autism-childhood-vaccines-tylenol)
3. [Nearly 7 in 10 COVID survivors tested didn't know they had a dulled sense of smell Changes in, or loss of, sense of smell can have a profound impact on a person's well-being, the authors say. Mary Van Beusekom September 26, 2025 ](https://www.cidrap.umn.edu/covid-19/nearly-7-10-covid-survivors-tested-didnt-know-they-had-dulled-sense-smell)
4. [US COVID declining after reaching peak In other developments, the CDC reported one more pediatric flu death, raising the season's total to 281, the highest for a nonpandemic year. Lisa Schnirring September 26, 2025](https://www.cidrap.umn.edu/covid-19/us-covid-declining-after-reaching-peak)
5. [H5N1 strikes more turkeys in 2 states In other developments, Canadian officials announce that the D1.3 genotype was identified in recent samples from ostriches at the center of a firestorm over culling. Lisa Schnirring September 29, 2025 ](https://www.cidrap.umn.edu/avian-influenza-bird-flu/h5n1-strikes-more-turkeys-2-states)
6. [Los Angeles cat H5N1 deaths prompt new warning about raw pet food Samples available for one of the cats revealed the B3.13 genotype, and genetic sequencing at the USDA lab is underway. Lisa Schnirring September 26, 2025 ](https://www.cidrap.umn.edu/avian-influenza-bird-flu/los-angeles-cat-h5n1-deaths-prompt-new-warning-about-raw-pet-food)
7. [COVID-19 infection associated with increased risk of new-onset vascular dementia in older adults Prior COVID-19 infection was associated with a 41% increased risk of all-cause dementia. Stephanie Soucheray October 2, 2025](https://www.cidrap.umn.edu/covid-19/covid-19-infection-associated-increased-risk-new-onset-vascular-dementia-older-adults)
8. [CDC confirms 23 more US measles cases as 2025 total tops 1,500 Georgia's health department reports 3 new measles infections with links to the state's most recent case. Stephanie Soucheray September 24, 2025](https://www.cidrap.umn.edu/measles/cdc-confirms-23-more-us-measles-cases-2025-total-tops-1500)
9. [CDC reports highlight 2024-25 flu season's deadly impact on US kids The reports provide more detail on the deadliest flu season for US children in more than a decade. Chris Dall September 26, 2025 ](https://www.cidrap.umn.edu/influenza-general/cdc-reports-highlight-2024-25-flu-seasons-deadly-impact-us-kids)
10. [HHS to furlough 41% of workforce during federal government shutdown Federal health officials say critical activities related to public health emergencies will continue, but non-critical activities will be significantly affected. Chris Dall October 1, 2025 ](https://www.cidrap.umn.edu/public-health/hhs-furlough-41-workforce-during-federal-government-shutdown)
## Our underwriters
### Unrestricted financial support provided by
[ Principal Underwriter](https://bentsonfoundation.org/ "(opens in a new window)")
[ Leading Underwriter](https://www.unorthodoxphilanthropy.org/ "(opens in a new window)")
[ Major Underwriter](https://www.3m.com/ "(opens in a new window)")
[ Supporting Underwriter](https://www.gilead.com/ "(opens in a new window)")

Supporting Underwriter
[Become an Underwriter](https://www.cidrap.umn.edu/support-cidrap)

## Help make CIDRAP's vital work possible
[Support Us](https://www.cidrap.umn.edu/support)
- [Home](https://www.cidrap.umn.edu/)
- [Editorial policy](https://www.cidrap.umn.edu/editorial-policy)
- [Search news](https://www.cidrap.umn.edu/search)
[](https://www.cidrap.umn.edu/cidrap-facebook)
[](https://www.cidrap.umn.edu/cidrap-twitter)
[](https://www.cidrap.umn.edu/cidrap-bluesky)
[](https://www.cidrap.umn.edu/cidrap-youtube)
[](https://www.linkedin.com/company/center-for-infectious-disease-research-and-policy-cidrap-?original_referer=https%3A//www.google.com/ "(opens in a new window)")
[](https://www.cidrap.umn.edu/rss-feeds)
## Contact Us
CIDRAP - Center for Infectious Disease Research & Policy
Research and Innovation Office, University of Minnesota, Minneapolis, MN
[Email us](https://www.cidrap.umn.edu/contact-us "Contact Us")
© 2025 Regents of the University of Minnesota. All rights Reserved.
The University of Minnesota is an equal opportunity educator and employer
[Research and Innovation Office](https://research.umn.edu/ "Research and Innovation Office (opens in a new window)") \| [Contact U of M](http://www.umn.edu/twincities/contact/ "Contact U of M (opens in a new window)") \| [Privacy Policy](https://www.cidrap.umn.edu/privacy-policy "Privacy Policy")
[Newsletter subscribe](https://www.cidrap.umn.edu/newsletter)
Get CIDRAP updates
##
CLOSE
[Close menu](https://www.cidrap.umn.edu/no-anaphylaxis-after-second-dose-mrna-covid-vaccine-study-finds#mm-0) |
| Readable Markdown | null |
| Shard | 45 (laksa) |
| Root Hash | 1624480930799954845 |
| Unparsed URL | edu,umn!cidrap,www,/no-anaphylaxis-after-second-dose-mrna-covid-vaccine-study-finds s443 |