🕷️ Crawler Inspector

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Direct Parameter Lookup

Raw Queries and Responses

1. Shard Calculation

Query:

Response:

Calculated Shard: 110 (from laksa018)

2. Crawled Status Check

Query:

curl -X POST \
  'http://laksa110.int.ahrefs:8124/' \
  -H 'Content-Type: text/plain' \
  -H 'X-ClickHouse-Database: crawler3' \
  -H 'Authorization: Basic YXBpOg==' \
  -d 'SELECT getAhrefsURLFromUnparsed(src_unparsed) AS found_url, ifNull(toUnixTimestamp(download_stamp), 0) AS crawl_time, ifNull(toUnixTimestamp(props_url_first_seen), 0) AS first_indexed_time, download_http_code AS http_code, src_unparsed AS src_unparsed, src_root_hash AS src_root_hash, history_drop_reason AS history_drop_reason, meta_title AS meta_title, meta_descriptions AS meta_descriptions, attrs_boilerpipe_text AS attrs_boilerpipe_text, attrs_markdown AS attrs_markdown, attrs_readable_markdown AS attrs_readable_markdown, meta_canonical AS meta_canonical, ml_categories_json AS ml_categories_json, ml_types_json AS ml_types_json, ml_intent_types_json AS ml_intent_types_json, meta_language AS meta_language, attrs_author AS attrs_author, ifNull(toUnixTimestamp(attrs_publish_time), 0) AS attrs_publish_time, ifNull(toUnixTimestamp(attrs_original_publish_time), 0) AS attrs_original_publish_time, ifNull(attrs_is_republished, 0) AS attrs_is_republished, ifNull(attrs_nr_words, 0) AS attrs_nr_words, ifNull(attrs_boilerpipe_nr_words, 0) AS attrs_boilerpipe_nr_words, ifNull(body_ext_links_number, 0) AS body_ext_links_number, ifNull(body_int_links_number, 0) AS body_int_links_number, ifNull(meta_nofollow, 0) AS meta_nofollow, ifNull(meta_noarchive, 0) AS meta_noarchive, ifNull(props_was_rendered, 0) AS props_was_rendered, ifNull(src_redirect, \'\') AS src_redirect, ifNull(download_time_msec, 0) AS download_time_msec, ifNull(download_ttfb_msec, 0) AS download_ttfb_msec, ifNull(download_size, 0) AS download_size FROM crawler3.page_info_local FINAL PREWHERE (src_root_hash, src_unparsed) IN ((getAhrefsRootHashFromUnparsed(getAhrefsUnparsedNoserviceFromURL(\'https://www.medicalnewstoday.com/articles/sinovac-covid-19-vaccine-what-are-the-side-effects\')), getAhrefsUnparsedNoserviceFromURL(\'https://www.medicalnewstoday.com/articles/sinovac-covid-19-vaccine-what-are-the-side-effects\'))) FORMAT JSONEachRow'

Response:

{"found_url":"https:\/\/www.medicalnewstoday.com\/articles\/sinovac-covid-19-vaccine-what-are-the-side-effects","crawl_time":1775022947,"first_indexed_time":1623484287,"http_code":200,"src_unparsed":"com,medicalnewstoday!www,\/articles\/sinovac-covid-19-vaccine-what-are-the-side-effects s443","src_root_hash":"5853625527623639710","history_drop_reason":null,"meta_title":"Sinovac (CoronaVac) COVID-19 vaccine: Safety and side effects","meta_descriptions":["This Snapshot feature outlines the known side effects of CoronaVac, the COVID-19 vaccine developed by Chinese biotechnology company Sinovac."],"attrs_boilerpipe_text":"This Snapshot article discusses the safety and side effects of CoronaVac, a COVID-19 vaccine that was recently validated by the World Health Organization (WHO) to protect against the SARS-CoV-2 virus.\nShare on Pinterest\nWhat do we know about Sinovac’s COVID-19 vaccine, CoronaVac?\nImage credit: CHAIDEER MAHYUDDIN\/Getty Images\nCoronaVac is a COVID-19 vaccine produced by\nSinovac Biotech\n, a China-based pharmaceutical company with headquarters in Beijing. The company focuses specifically on the development and manufacturing of vaccines to target human infectious diseases.\nThis two-dose vaccine is recommended for individuals aged 18 years and above. It has an efficacy rate of\n50.4%\nfor preventing symptomatic infection, according to data from a Brazilian trial, and an effectiveness of\n67%\n, according to a real-world study in Chile.\nSinovac’s vaccine was validated for Emergency Use Listing (EUL) by the\nWHO\non June 1. WHO’s EUL procedure for CoronaVac included a review of the vaccine’s safety and efficacy, as well as “onsite inspections of the production facility.”\nThe Strategic Advisory Group of Experts on Immunization (SAGE), WHO’s main advisory board regarding vaccines, also reviewed the vaccine as part of WHO’s EUL validation.\nAs of January 2022, the vaccine is approved for use in\n52 countries\n.\nCoronaVac is an\ninactivated vaccine\n. It uses a dead version of the\nSARS\n-CoV-2 virus so that it cannot replicate, but it keeps the surface spike protein intact to trigger the body’s immune system to create antibodies for protection against the live virus, if it were to invade.\nPhase 1 and 2 clinical trial data for the vaccine, published in\nThe Lancet\nin February 2021, reveal some of the side effects reported by trial participants.\nAccording to the data, the most common side effect reported within 28 days of the second dose was injection-site pain (13–21%, depending on the dosing schedule). Injection site reactions are common with other COVID-19 vaccines, including the\ntwo inactivated COVID-19 vaccines by Sinopharm\n.\nOther side effects included\nfatigue\n,\ndiarrhea\n, and muscle pain. Most of these side effects were mild and lasted only for 2 days.\nAdditionally, the paper notes that participants who received CoronaVac reported a lower occurrence of\nfever\nin comparison to other COVID-19 vaccines, including the mRNA-based vaccine from\nModerna\nand viral vector vaccines from\nOxford-AstraZeneca\nand CanSino.\nSimilar to other\nCOVID-19 vaccines approved by WHO\n, the global health agency recommends the CoronaVac vaccine for people with comorbidities, those who are immunocompromised, or those who previously have had COVID-19.\nThe WHO also recommends CoronaVac for people living with\nHIV\n. It states that while the trials reviewed by SAGE did not include this specific population, CoronaVac is a nonreplicating vaccine and can be recommended.\nThe WHO also notes that while this vaccine has not been sufficiently tested in pregnant people, its similarity to other vaccines deemed safe, such as those for\nhepatitis B\n, suggests that there are no expected concerns for the use of the vaccine during pregnancy.\nUntil studies have adequately evaluated the safety of CoronaVac in pregnant individuals, the WHO recommends its use when the benefits of vaccination outweigh the potential risks.\nAs with other authorized COVID-19 vaccines, individuals with a history of\nanaphylaxis\nto any of the vaccine’s ingredients should not receive the vaccine.\nAn\narticle\nby the\nGlobal Times\nnotes that, according to phase 2 clinical trials for the vaccine, a booster shot of CoronaVac after the initial two doses may boost antibody levels, with a tenfold increase in activity a week after the shot.\nSinovac plans to continue its clinical trials to determine the efficacy and timing of the booster shot, as well as the vaccine’s effectiveness against emerging SARS-CoV-2 variants.\nPhase 3 clinical trial data for the vaccine will likely provide further insight into the efficacy and safety profile of the vaccine.\nSince experts named\nOmicron\na SARS-CoV-2 variant of concern, researchers have been looking into whether or not CoronaVac is effective against Omicron.\nA paper published in\nNature Medicine\nin January 2022 indicates that two doses of CoronaVac could not neutralize the Omicron variant.\n“Notably, none of the individuals fully vaccinated with CoronaVac [whose data the study analyzed] had detectable neutralizing [antibodies] against [the] SARS-CoV-2 Omicron variant,” the paper authors write.\nAdding a booster dose of the Pfizer-BioNTech mRNA vaccine somewhat improved the immune response to this variant. Still, participants had significantly reduced neutralization antibodies against Omicron compared with those produced against the Delta variant, suggesting a greater risk of vaccine breakthrough infections, the researchers warn.\nFor live updates on the latest developments regarding the novel coronavirus and COVID-19, click\nhere\n.","attrs_markdown":"- Health Conditions\n  Health Conditions\n  \n  - [Alzheimer's & Dementia](https:\/\/www.medicalnewstoday.com\/alzheimers-and-dementia)\n  - [Anxiety](https:\/\/www.medicalnewstoday.com\/anxiety)\n  - [Asthma & Allergies](https:\/\/www.medicalnewstoday.com\/asthma-and-allergies)\n  - [Atopic Dermatitis](https:\/\/www.medicalnewstoday.com\/program\/investigating-atopic-dermatitis)\n  - [Breast Cancer](https:\/\/www.medicalnewstoday.com\/breast-cancer)\n  - [Cancer](https:\/\/www.medicalnewstoday.com\/cancer)\n  - [Cardiovascular Health](https:\/\/www.medicalnewstoday.com\/cardiovascular-health)\n  - [COVID-19](https:\/\/www.medicalnewstoday.com\/coronavirus?correlationId=2b137d5a-dcfb-464e-9ea6-72c5a54b4e92)\n  - 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[Ankylosing Spondylitis Pain: Fact or Fiction](https:\/\/www.medicalnewstoday.com\/articles\/complementary-therapies-for-as-quiz#1)\n- Connect\n  About Medical News Today\n  \n  - [Who We Are](https:\/\/www.medicalnewstoday.com\/about)\n  - [Our Editorial Process](https:\/\/www.medicalnewstoday.com\/articles\/process)\n  - [Content Integrity](https:\/\/www.medicalnewstoday.com\/about\/content-integrity)\n  - [Conscious Language](https:\/\/www.medicalnewstoday.com\/about\/conscious-language)\n  \n  Find Community\n  \n  - [Bezzy Breast Cancer](https:\/\/www.bezzybc.com\/lp\/2\/?verzenio&utm_source=mnt&utm_medium=nav-bar-connect)\n  - [Bezzy MS](https:\/\/www.bezzyms.com\/?utm_source=mnt&utm_medium=nav-bar-connect)\n  - [Bezzy Migraine](https:\/\/www.bezzymigraine.com\/?utm_source=mnt&utm_medium=nav-bar-connect)\n  - [Bezzy Psoriasis](https:\/\/www.bezzypsoriasis.com\/?utm_source=mnt&utm_medium=nav-bar-connect)\n  \n  Follow Us\n\nSubscribe\n\n# Sinovac COVID-19 vaccine: What are the side effects?\nWritten by Minseo Jeong — Fact checked by Harriet Pike, Ph.D. —  [Updated on January 27, 2022]()\n\nThis Snapshot article discusses the safety and side effects of CoronaVac, a COVID-19 vaccine that was recently validated by the World Health Organization (WHO) to protect against the SARS-CoV-2 virus.\n\n![](https:\/\/i0.wp.com\/post.medicalnewstoday.com\/wp-content\/uploads\/sites\/3\/2021\/06\/GettyImages-1233312949_header-1024x575.jpg?w=1155&h=1528)\n\n[Share on Pinterest](https:\/\/www.pinterest.com\/pin\/create\/button\/?url=https%3A%2F%2Fwww.medicalnewstoday.com%2Farticles%2Fsinovac-covid-19-vaccine-what-are-the-side-effects&media=https%3A%2F%2Fpost.medicalnewstoday.com%2Fwp-content%2Fuploads%2Fsites%2F3%2F2021%2F06%2FGettyImages-1233312949_header-1024x575.jpg&description=Sinovac%20\\(CoronaVac\\)%20COVID-19%20vaccine%3A%20Safety%20and%20side%20effects \"Share on Pinterest\")\n\nWhat do we know about Sinovac’s COVID-19 vaccine, CoronaVac?  \nImage credit: CHAIDEER MAHYUDDIN\/Getty Images\n\n### Coronavirus data\nAll data and statistics are based on publicly available data at the time of publication. Some information may be out of date. Visit our [coronavirus hub](https:\/\/www.medicalnewstoday.com\/coronavirus) for the most recent information on COVID-19.\n\nCoronaVac is a COVID-19 vaccine produced by [Sinovac Biotech](http:\/\/www.sinovac.com\/index.php?lang=en), a China-based pharmaceutical company with headquarters in Beijing. The company focuses specifically on the development and manufacturing of vaccines to target human infectious diseases.\n\nThis two-dose vaccine is recommended for individuals aged 18 years and above. It has an efficacy rate of [50\\.4%](https:\/\/www.reuters.com\/business\/healthcare-pharmaceuticals\/new-brazil-data-shows-disappointing-504-efficacy-chinas-coronavac-vaccine-2021-01-12\/) for preventing symptomatic infection, according to data from a Brazilian trial, and an effectiveness of [67%](https:\/\/www.reuters.com\/business\/healthcare-pharmaceuticals\/chinas-sinovac-covid-19-vaccine-67-effective-preventing-symptomatic-infection-2021-04-16\/), according to a real-world study in Chile.\n\nSinovac’s vaccine was validated for Emergency Use Listing (EUL) by the [WHO](https:\/\/www.who.int\/news\/item\/01-06-2021-who-validates-sinovac-covid-19-vaccine-for-emergency-use-and-issues-interim-policy-recommendations) on June 1. WHO’s EUL procedure for CoronaVac included a review of the vaccine’s safety and efficacy, as well as “onsite inspections of the production facility.”\n\nThe Strategic Advisory Group of Experts on Immunization (SAGE), WHO’s main advisory board regarding vaccines, also reviewed the vaccine as part of WHO’s EUL validation.\n\nAs of January 2022, the vaccine is approved for use in [52 countries](https:\/\/covid19.trackvaccines.org\/vaccines\/7\/).\n\nCoronaVac is an [inactivated vaccine](https:\/\/www.medicalnewstoday.com\/articles\/mnt-620130). It uses a dead version of the [SARS](https:\/\/www.medicalnewstoday.com\/articles\/7543)\\-CoV-2 virus so that it cannot replicate, but it keeps the surface spike protein intact to trigger the body’s immune system to create antibodies for protection against the live virus, if it were to invade.\n\n### Coronavirus resources\nFor more advice on COVID-19 prevention and treatment, visit our [coronavirus hub](https:\/\/www.medicalnewstoday.com\/coronavirus).\n\n## [Common side effects]()\nPhase 1 and 2 clinical trial data for the vaccine, published in *[The Lancet](https:\/\/www.thelancet.com\/article\/S1473-3099\\(20\\)30843-4\/fulltext)* in February 2021, reveal some of the side effects reported by trial participants.\n\n**According to the data, the most common side effect reported within 28 days of the second dose was injection-site pain (13–21%, depending on the dosing schedule). Injection site reactions are common with other COVID-19 vaccines, including the [two inactivated COVID-19 vaccines by Sinopharm](https:\/\/www.medicalnewstoday.com\/articles\/global-covid-19-vaccine-summary-side-effects#Currently-authorized-COVID-19-vaccines).**\n\nOther side effects included [fatigue](https:\/\/www.medicalnewstoday.com\/articles\/248002), [diarrhea](https:\/\/www.medicalnewstoday.com\/articles\/158634), and muscle pain. Most of these side effects were mild and lasted only for 2 days.\n\nAdditionally, the paper notes that participants who received CoronaVac reported a lower occurrence of [fever](https:\/\/www.medicalnewstoday.com\/articles\/168266) in comparison to other COVID-19 vaccines, including the mRNA-based vaccine from [Moderna](https:\/\/www.medicalnewstoday.com\/articles\/moderna-covid-19-vaccine-what-to-know-about-side-effects) and viral vector vaccines from [Oxford-AstraZeneca](https:\/\/www.medicalnewstoday.com\/articles\/oxford-astrazeneca-vaccine-what-to-know-about-side-effects) and CanSino.\n\n## [Who can receive the vaccine?]()\nSimilar to other [COVID-19 vaccines approved by WHO](https:\/\/www.who.int\/news-room\/feature-stories\/detail\/the-sinovac-covid-19-vaccine-what-you-need-to-know), the global health agency recommends the CoronaVac vaccine for people with comorbidities, those who are immunocompromised, or those who previously have had COVID-19.\n\nThe WHO also recommends CoronaVac for people living with [HIV](https:\/\/www.medicalnewstoday.com\/articles\/17131). It states that while the trials reviewed by SAGE did not include this specific population, CoronaVac is a nonreplicating vaccine and can be recommended.\n\nThe WHO also notes that while this vaccine has not been sufficiently tested in pregnant people, its similarity to other vaccines deemed safe, such as those for [hepatitis B](https:\/\/www.medicalnewstoday.com\/articles\/306288), suggests that there are no expected concerns for the use of the vaccine during pregnancy.\n\nUntil studies have adequately evaluated the safety of CoronaVac in pregnant individuals, the WHO recommends its use when the benefits of vaccination outweigh the potential risks.\n\nAs with other authorized COVID-19 vaccines, individuals with a history of [anaphylaxis](https:\/\/www.medicalnewstoday.com\/articles\/216062) to any of the vaccine’s ingredients should not receive the vaccine.\n\n## [Next steps in CoronaVac trials]()\nAn [article](https:\/\/www.globaltimes.cn\/page\/202106\/1225472.shtml) by the *Global Times* notes that, according to phase 2 clinical trials for the vaccine, a booster shot of CoronaVac after the initial two doses may boost antibody levels, with a tenfold increase in activity a week after the shot.\n\nSinovac plans to continue its clinical trials to determine the efficacy and timing of the booster shot, as well as the vaccine’s effectiveness against emerging SARS-CoV-2 variants.\n\nPhase 3 clinical trial data for the vaccine will likely provide further insight into the efficacy and safety profile of the vaccine.\n\n## [CoronaVac and Omicron]()\nSince experts named [Omicron](https:\/\/www.medicalnewstoday.com\/articles\/covid-19-why-the-omicron-variant-has-scientists-worried) a SARS-CoV-2 variant of concern, researchers have been looking into whether or not CoronaVac is effective against Omicron.\n\nA paper published in *[Nature Medicine](https:\/\/www.nature.com\/articles\/s41591-022-01705-6)* in January 2022 indicates that two doses of CoronaVac could not neutralize the Omicron variant.\n\n**“Notably, none of the individuals fully vaccinated with CoronaVac \\[whose data the study analyzed\\] had detectable neutralizing \\[antibodies\\] against \\[the\\] SARS-CoV-2 Omicron variant,” the paper authors write.**\n\nAdding a booster dose of the Pfizer-BioNTech mRNA vaccine somewhat improved the immune response to this variant. Still, participants had significantly reduced neutralization antibodies against Omicron compared with those produced against the Delta variant, suggesting a greater risk of vaccine breakthrough infections, the researchers warn.\n\n***For live updates on the latest developments regarding the novel coronavirus and COVID-19, click [here](https:\/\/www.medicalnewstoday.com\/articles\/live-updates-coronavirus-covid-19).***\n\n- [Public Health](https:\/\/www.medicalnewstoday.com\/categories\/public-health)\n- [Immune System \/ Vaccines](https:\/\/www.medicalnewstoday.com\/categories\/immune-system)\n- [Infectious Diseases \/ Bacteria \/ Viruses](https:\/\/www.medicalnewstoday.com\/categories\/infectious_diseases)\n- [COVID-19](https:\/\/www.medicalnewstoday.com\/categories\/covid-19)\n\nShare this article\n\nWritten by Minseo Jeong — Fact checked by Harriet Pike, Ph.D. —  [Updated on January 27, 2022]()\n\n## Latest news\n- [9 steps to improve heart health, per new dietary guidance from AHA](https:\/\/www.medicalnewstoday.com\/articles\/9-steps-improve-heart-health-diet-guidance-aha)\n- [AI model can accurately predict liver cancer risk, study suggests](https:\/\/www.medicalnewstoday.com\/articles\/ai-model-accurately-predict-liver-cancer-risk)\n- [AI-powered stroke tool linked to improved patient outcomes in large clinical trial](https:\/\/www.medicalnewstoday.com\/articles\/ai-powered-stroke-tool-linked-improved-patient-outcomes-large-clinical-trial)\n- [Eating same meals on repeat, and more at weekends may help you lose more weight](https:\/\/www.medicalnewstoday.com\/articles\/eating-same-meals-repeat-more-weekends-may-help-lose-more-weight)\n- [Cooking at least one meal at home weekly may cut dementia risk by up to 67%](https:\/\/www.medicalnewstoday.com\/articles\/cooking-at-least-one-meal-at-home-weekly-may-cut-dementia-risk)\n\n### Related Coverage\n- [Covaxin COVID-19 vaccine: What to know about side effects](https:\/\/www.medicalnewstoday.com\/articles\/covaxin-covid-19-vaccine-what-to-know-about-side-effects?utm_source=ReadNext)\n  \n  [In this Snapshot feature, we provide an overview of the Covaxin inactivated virus vaccine for COVID-19 and its possible side effects.](https:\/\/www.medicalnewstoday.com\/articles\/covaxin-covid-19-vaccine-what-to-know-about-side-effects?utm_source=ReadNext)\n  \n  [READ MORE](https:\/\/www.medicalnewstoday.com\/articles\/covaxin-covid-19-vaccine-what-to-know-about-side-effects?utm_source=ReadNext)\n- [Johnson & Johnson COVID-19 vaccine: What are the side effects?](https:\/\/www.medicalnewstoday.com\/articles\/johnson-johnson-covid-19-vaccine-what-are-the-side-effects?utm_source=ReadNext)\n  \n  [In this Spotlight feature, we offer an overview of the possible side effects of the Johnson & Johnson COVID-19 vaccine and discuss whether the vaccine…](https:\/\/www.medicalnewstoday.com\/articles\/johnson-johnson-covid-19-vaccine-what-are-the-side-effects?utm_source=ReadNext)\n  \n  [READ MORE](https:\/\/www.medicalnewstoday.com\/articles\/johnson-johnson-covid-19-vaccine-what-are-the-side-effects?utm_source=ReadNext)\n- [Oxford-AstraZeneca vaccine: What to know about side effects](https:\/\/www.medicalnewstoday.com\/articles\/oxford-astrazeneca-vaccine-what-to-know-about-side-effects?utm_source=ReadNext)\n  \n  [In this Snapshot, we take a closer look at the potential side effects associated with the Oxford-AstraZeneca COVID-19 vaccine, also known as Vaxzevria.](https:\/\/www.medicalnewstoday.com\/articles\/oxford-astrazeneca-vaccine-what-to-know-about-side-effects?utm_source=ReadNext)\n  \n  [READ MORE](https:\/\/www.medicalnewstoday.com\/articles\/oxford-astrazeneca-vaccine-what-to-know-about-side-effects?utm_source=ReadNext)\n- [Moderna COVID-19 vaccine: What to know about side effects](https:\/\/www.medicalnewstoday.com\/articles\/moderna-covid-19-vaccine-what-to-know-about-side-effects?utm_source=ReadNext)\n  \n  [In this feature, we highlight the most common side effects of the Moderna COVID-19 vaccine. We also explore how common they are and other safety…](https:\/\/www.medicalnewstoday.com\/articles\/moderna-covid-19-vaccine-what-to-know-about-side-effects?utm_source=ReadNext)\n  \n  [READ MORE](https:\/\/www.medicalnewstoday.com\/articles\/moderna-covid-19-vaccine-what-to-know-about-side-effects?utm_source=ReadNext)\n- [What is the Nipah virus and what is the risk of a global outbreak?](https:\/\/www.medicalnewstoday.com\/articles\/what-is-the-nipah-virus-and-what-is-the-risk-of-a-global-outbreak?utm_source=ReadNext)\n  \n  [Following the Nipah virus outbreak in India, we asked experts about ongoing research into treatments, if there is a cause for concern, and whether…](https:\/\/www.medicalnewstoday.com\/articles\/what-is-the-nipah-virus-and-what-is-the-risk-of-a-global-outbreak?utm_source=ReadNext)\n  \n  [READ MORE](https:\/\/www.medicalnewstoday.com\/articles\/what-is-the-nipah-virus-and-what-is-the-risk-of-a-global-outbreak?utm_source=ReadNext)\n\n© 2026 Healthline Media UK Ltd, London, UK. All rights reserved. MNT is the registered trade mark of Healthline Media. Healthline Media is an RVO Health Company. Any medical information published on this website is not intended as a substitute for informed medical advice and you should not take any action before consulting with a healthcare professional. [See additional information](https:\/\/www.medicalnewstoday.com\/about\/additional-information).\n\n- [About Us](https:\/\/www.medicalnewstoday.com\/about)\n- [Contact Us](https:\/\/www.medicalnewstoday.com\/about\/contact-us)\n- [Terms of Use](https:\/\/www.medicalnewstoday.com\/about\/terms-of-use)\n- [Privacy Policy](https:\/\/www.medicalnewstoday.com\/about\/privacy-policy)\n- Privacy Settings\n- [Advertising Policy](https:\/\/www.medicalnewstoday.com\/ad-policy)\n\n- [Health Topics](https:\/\/www.medicalnewstoday.com\/directory\/a-b)\n- [Health Hubs](https:\/\/www.medicalnewstoday.com\/articles\/content-hubs)\n- [Medical Affairs](https:\/\/www.medicalnewstoday.com\/about\/reviewers)\n- [Content Integrity](https:\/\/www.medicalnewstoday.com\/about\/content-integrity)\n- [Newsletters](https:\/\/www.medicalnewstoday.com\/newsletter)\n- © 2026 Healthline Media UK Ltd, London, UK. All rights reserved. MNT is the registered trade mark of Healthline Media. Healthline Media is an RVO Health Company. Any medical information published on this website is not intended as a substitute for informed medical advice and you should not take any action before consulting with a healthcare professional. [See additional information](https:\/\/www.medicalnewstoday.com\/about\/additional-information).\n\n© 2026 Healthline Media UK Ltd, London, UK. All rights reserved. MNT is the registered trade mark of Healthline Media. Healthline Media is an RVO Health Company. Any medical information published on this website is not intended as a substitute for informed medical advice and you should not take any action before consulting with a healthcare professional. [See additional information](https:\/\/www.medicalnewstoday.com\/about\/additional-information).\n\n[About](https:\/\/www.healthlinemedia.com\/?utm_source=medicalnewstoday.com&utm_medium=site&utm_campaign=footer&utm_content=about)[Careers](https:\/\/rvohealth.com\/careers)[Advertise with us](https:\/\/www.healthlinemedia.com\/advertise?utm_source=medicalnewstoday.com&utm_medium=site&utm_campaign=footer&utm_content=advertise)\n\nOUR BRANDS\n\n[Healthline](https:\/\/www.healthline.com\/)[Medical News Today](https:\/\/www.medicalnewstoday.com\/)[Greatist](https:\/\/greatist.com\/)[Psych Central](https:\/\/psychcentral.com\/)[Bezzy](https:\/\/bezzy.com\/)\n\n![](http:\/\/b.scorecardresearch.com\/p?c1=2&c2=38584006&cv=3.9&cj=1&comscorekw=main)","attrs_readable_markdown":"This Snapshot article discusses the safety and side effects of CoronaVac, a COVID-19 vaccine that was recently validated by the World Health Organization (WHO) to protect against the SARS-CoV-2 virus.\n\n![](https:\/\/i0.wp.com\/post.medicalnewstoday.com\/wp-content\/uploads\/sites\/3\/2021\/06\/GettyImages-1233312949_header-1024x575.jpg?w=1155&h=1528)\n\n[Share on Pinterest](https:\/\/www.pinterest.com\/pin\/create\/button\/?url=https%3A%2F%2Fwww.medicalnewstoday.com%2Farticles%2Fsinovac-covid-19-vaccine-what-are-the-side-effects&media=https%3A%2F%2Fpost.medicalnewstoday.com%2Fwp-content%2Fuploads%2Fsites%2F3%2F2021%2F06%2FGettyImages-1233312949_header-1024x575.jpg&description=Sinovac%20\\(CoronaVac\\)%20COVID-19%20vaccine%3A%20Safety%20and%20side%20effects \"Share on Pinterest\")\n\nWhat do we know about Sinovac’s COVID-19 vaccine, CoronaVac?  \nImage credit: CHAIDEER MAHYUDDIN\/Getty Images\n\nCoronaVac is a COVID-19 vaccine produced by [Sinovac Biotech](http:\/\/www.sinovac.com\/index.php?lang=en), a China-based pharmaceutical company with headquarters in Beijing. The company focuses specifically on the development and manufacturing of vaccines to target human infectious diseases.\n\nThis two-dose vaccine is recommended for individuals aged 18 years and above. It has an efficacy rate of [50\\.4%](https:\/\/www.reuters.com\/business\/healthcare-pharmaceuticals\/new-brazil-data-shows-disappointing-504-efficacy-chinas-coronavac-vaccine-2021-01-12\/) for preventing symptomatic infection, according to data from a Brazilian trial, and an effectiveness of [67%](https:\/\/www.reuters.com\/business\/healthcare-pharmaceuticals\/chinas-sinovac-covid-19-vaccine-67-effective-preventing-symptomatic-infection-2021-04-16\/), according to a real-world study in Chile.\n\nSinovac’s vaccine was validated for Emergency Use Listing (EUL) by the [WHO](https:\/\/www.who.int\/news\/item\/01-06-2021-who-validates-sinovac-covid-19-vaccine-for-emergency-use-and-issues-interim-policy-recommendations) on June 1. WHO’s EUL procedure for CoronaVac included a review of the vaccine’s safety and efficacy, as well as “onsite inspections of the production facility.”\n\nThe Strategic Advisory Group of Experts on Immunization (SAGE), WHO’s main advisory board regarding vaccines, also reviewed the vaccine as part of WHO’s EUL validation.\n\nAs of January 2022, the vaccine is approved for use in [52 countries](https:\/\/covid19.trackvaccines.org\/vaccines\/7\/).\n\nCoronaVac is an [inactivated vaccine](https:\/\/www.medicalnewstoday.com\/articles\/mnt-620130). It uses a dead version of the [SARS](https:\/\/www.medicalnewstoday.com\/articles\/7543)\\-CoV-2 virus so that it cannot replicate, but it keeps the surface spike protein intact to trigger the body’s immune system to create antibodies for protection against the live virus, if it were to invade.\n\n##\nPhase 1 and 2 clinical trial data for the vaccine, published in *[The Lancet](https:\/\/www.thelancet.com\/article\/S1473-3099\\(20\\)30843-4\/fulltext)* in February 2021, reveal some of the side effects reported by trial participants.\n\n**According to the data, the most common side effect reported within 28 days of the second dose was injection-site pain (13–21%, depending on the dosing schedule). Injection site reactions are common with other COVID-19 vaccines, including the [two inactivated COVID-19 vaccines by Sinopharm](https:\/\/www.medicalnewstoday.com\/articles\/global-covid-19-vaccine-summary-side-effects#Currently-authorized-COVID-19-vaccines).**\n\nOther side effects included [fatigue](https:\/\/www.medicalnewstoday.com\/articles\/248002), [diarrhea](https:\/\/www.medicalnewstoday.com\/articles\/158634), and muscle pain. Most of these side effects were mild and lasted only for 2 days.\n\nAdditionally, the paper notes that participants who received CoronaVac reported a lower occurrence of [fever](https:\/\/www.medicalnewstoday.com\/articles\/168266) in comparison to other COVID-19 vaccines, including the mRNA-based vaccine from [Moderna](https:\/\/www.medicalnewstoday.com\/articles\/moderna-covid-19-vaccine-what-to-know-about-side-effects) and viral vector vaccines from [Oxford-AstraZeneca](https:\/\/www.medicalnewstoday.com\/articles\/oxford-astrazeneca-vaccine-what-to-know-about-side-effects) and CanSino.\n\n##\nSimilar to other [COVID-19 vaccines approved by WHO](https:\/\/www.who.int\/news-room\/feature-stories\/detail\/the-sinovac-covid-19-vaccine-what-you-need-to-know), the global health agency recommends the CoronaVac vaccine for people with comorbidities, those who are immunocompromised, or those who previously have had COVID-19.\n\nThe WHO also recommends CoronaVac for people living with [HIV](https:\/\/www.medicalnewstoday.com\/articles\/17131). It states that while the trials reviewed by SAGE did not include this specific population, CoronaVac is a nonreplicating vaccine and can be recommended.\n\nThe WHO also notes that while this vaccine has not been sufficiently tested in pregnant people, its similarity to other vaccines deemed safe, such as those for [hepatitis B](https:\/\/www.medicalnewstoday.com\/articles\/306288), suggests that there are no expected concerns for the use of the vaccine during pregnancy.\n\nUntil studies have adequately evaluated the safety of CoronaVac in pregnant individuals, the WHO recommends its use when the benefits of vaccination outweigh the potential risks.\n\nAs with other authorized COVID-19 vaccines, individuals with a history of [anaphylaxis](https:\/\/www.medicalnewstoday.com\/articles\/216062) to any of the vaccine’s ingredients should not receive the vaccine.\n\n##\nAn [article](https:\/\/www.globaltimes.cn\/page\/202106\/1225472.shtml) by the *Global Times* notes that, according to phase 2 clinical trials for the vaccine, a booster shot of CoronaVac after the initial two doses may boost antibody levels, with a tenfold increase in activity a week after the shot.\n\nSinovac plans to continue its clinical trials to determine the efficacy and timing of the booster shot, as well as the vaccine’s effectiveness against emerging SARS-CoV-2 variants.\n\nPhase 3 clinical trial data for the vaccine will likely provide further insight into the efficacy and safety profile of the vaccine.\n\n##\nSince experts named [Omicron](https:\/\/www.medicalnewstoday.com\/articles\/covid-19-why-the-omicron-variant-has-scientists-worried) a SARS-CoV-2 variant of concern, researchers have been looking into whether or not CoronaVac is effective against Omicron.\n\nA paper published in *[Nature Medicine](https:\/\/www.nature.com\/articles\/s41591-022-01705-6)* in January 2022 indicates that two doses of CoronaVac could not neutralize the Omicron variant.\n\n**“Notably, none of the individuals fully vaccinated with CoronaVac \\[whose data the study analyzed\\] had detectable neutralizing \\[antibodies\\] against \\[the\\] SARS-CoV-2 Omicron variant,” the paper authors write.**\n\nAdding a booster dose of the Pfizer-BioNTech mRNA vaccine somewhat improved the immune response to this variant. Still, participants had significantly reduced neutralization antibodies against Omicron compared with those produced against the Delta variant, suggesting a greater risk of vaccine breakthrough infections, the researchers warn.\n\n***For live updates on the latest developments regarding the novel coronavirus and COVID-19, click [here](https:\/\/www.medicalnewstoday.com\/articles\/live-updates-coronavirus-covid-19).***","meta_canonical":null,"ml_categories_json":"{\"\/Health\":991,\"\/Health\/Public_Health\":704,\"\/Health\/Public_Health\/Health_Policy\":653}","ml_types_json":"{\"\/Article\":999,\"\/Article\/News_Update\":508}","ml_intent_types_json":"{\"Informational\":999}","meta_language":"en","attrs_author":"Minseo Jeong","attrs_publish_time":0,"attrs_original_publish_time":1623484287,"attrs_is_republished":0,"attrs_nr_words":"1600","attrs_boilerpipe_nr_words":"763","body_ext_links_number":34,"body_int_links_number":103,"meta_nofollow":0,"meta_noarchive":0,"props_was_rendered":0,"src_redirect":"","download_time_msec":525,"download_ttfb_msec":439,"download_size":59754}

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Sinovac (CoronaVac) COVID-19 vaccine: Safety and side effects

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This Snapshot feature outlines the known side effects of CoronaVac, the COVID-19 vaccine developed by Chinese biotechnology company Sinovac.

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This Snapshot article discusses the safety and side effects of CoronaVac, a COVID-19 vaccine that was recently validated by the World Health Organization (WHO) to protect against the SARS-CoV-2 virus. Share on Pinterest What do we know about Sinovac’s COVID-19 vaccine, CoronaVac? Image credit: CHAIDEER MAHYUDDIN/Getty Images CoronaVac is a COVID-19 vaccine produced by Sinovac Biotech , a China-based pharmaceutical company with headquarters in Beijing. The company focuses specifically on the development and manufacturing of vaccines to target human infectious diseases. This two-dose vaccine is recommended for individuals aged 18 years and above. It has an efficacy rate of 50.4% for preventing symptomatic infection, according to data from a Brazilian trial, and an effectiveness of 67% , according to a real-world study in Chile. Sinovac’s vaccine was validated for Emergency Use Listing (EUL) by the WHO on June 1. WHO’s EUL procedure for CoronaVac included a review of the vaccine’s safety and efficacy, as well as “onsite inspections of the production facility.” The Strategic Advisory Group of Experts on Immunization (SAGE), WHO’s main advisory board regarding vaccines, also reviewed the vaccine as part of WHO’s EUL validation. As of January 2022, the vaccine is approved for use in 52 countries . CoronaVac is an inactivated vaccine . It uses a dead version of the SARS -CoV-2 virus so that it cannot replicate, but it keeps the surface spike protein intact to trigger the body’s immune system to create antibodies for protection against the live virus, if it were to invade. Phase 1 and 2 clinical trial data for the vaccine, published in The Lancet in February 2021, reveal some of the side effects reported by trial participants. According to the data, the most common side effect reported within 28 days of the second dose was injection-site pain (13–21%, depending on the dosing schedule). Injection site reactions are common with other COVID-19 vaccines, including the two inactivated COVID-19 vaccines by Sinopharm . Other side effects included fatigue , diarrhea , and muscle pain. Most of these side effects were mild and lasted only for 2 days. Additionally, the paper notes that participants who received CoronaVac reported a lower occurrence of fever in comparison to other COVID-19 vaccines, including the mRNA-based vaccine from Moderna and viral vector vaccines from Oxford-AstraZeneca and CanSino. Similar to other COVID-19 vaccines approved by WHO , the global health agency recommends the CoronaVac vaccine for people with comorbidities, those who are immunocompromised, or those who previously have had COVID-19. The WHO also recommends CoronaVac for people living with HIV . It states that while the trials reviewed by SAGE did not include this specific population, CoronaVac is a nonreplicating vaccine and can be recommended. The WHO also notes that while this vaccine has not been sufficiently tested in pregnant people, its similarity to other vaccines deemed safe, such as those for hepatitis B , suggests that there are no expected concerns for the use of the vaccine during pregnancy. Until studies have adequately evaluated the safety of CoronaVac in pregnant individuals, the WHO recommends its use when the benefits of vaccination outweigh the potential risks. As with other authorized COVID-19 vaccines, individuals with a history of anaphylaxis to any of the vaccine’s ingredients should not receive the vaccine. An article by the Global Times notes that, according to phase 2 clinical trials for the vaccine, a booster shot of CoronaVac after the initial two doses may boost antibody levels, with a tenfold increase in activity a week after the shot. Sinovac plans to continue its clinical trials to determine the efficacy and timing of the booster shot, as well as the vaccine’s effectiveness against emerging SARS-CoV-2 variants. Phase 3 clinical trial data for the vaccine will likely provide further insight into the efficacy and safety profile of the vaccine. Since experts named Omicron a SARS-CoV-2 variant of concern, researchers have been looking into whether or not CoronaVac is effective against Omicron. A paper published in Nature Medicine in January 2022 indicates that two doses of CoronaVac could not neutralize the Omicron variant. “Notably, none of the individuals fully vaccinated with CoronaVac [whose data the study analyzed] had detectable neutralizing [antibodies] against [the] SARS-CoV-2 Omicron variant,” the paper authors write. Adding a booster dose of the Pfizer-BioNTech mRNA vaccine somewhat improved the immune response to this variant. Still, participants had significantly reduced neutralization antibodies against Omicron compared with those produced against the Delta variant, suggesting a greater risk of vaccine breakthrough infections, the researchers warn. For live updates on the latest developments regarding the novel coronavirus and COVID-19, click here .

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[Bezzy Psoriasis](https://www.bezzypsoriasis.com/?utm_source=mnt&utm_medium=nav-bar-connect) Follow Us Subscribe # Sinovac COVID-19 vaccine: What are the side effects? Written by Minseo Jeong — Fact checked by Harriet Pike, Ph.D. — [Updated on January 27, 2022]() This Snapshot article discusses the safety and side effects of CoronaVac, a COVID-19 vaccine that was recently validated by the World Health Organization (WHO) to protect against the SARS-CoV-2 virus. ![](https://i0.wp.com/post.medicalnewstoday.com/wp-content/uploads/sites/3/2021/06/GettyImages-1233312949_header-1024x575.jpg?w=1155&h=1528) [Share on Pinterest](https://www.pinterest.com/pin/create/button/?url=https%3A%2F%2Fwww.medicalnewstoday.com%2Farticles%2Fsinovac-covid-19-vaccine-what-are-the-side-effects&media=https%3A%2F%2Fpost.medicalnewstoday.com%2Fwp-content%2Fuploads%2Fsites%2F3%2F2021%2F06%2FGettyImages-1233312949_header-1024x575.jpg&description=Sinovac%20\(CoronaVac\)%20COVID-19%20vaccine%3A%20Safety%20and%20side%20effects "Share on Pinterest") What do we know about Sinovac’s COVID-19 vaccine, CoronaVac? Image credit: CHAIDEER MAHYUDDIN/Getty Images ### Coronavirus data All data and statistics are based on publicly available data at the time of publication. Some information may be out of date. Visit our [coronavirus hub](https://www.medicalnewstoday.com/coronavirus) for the most recent information on COVID-19. CoronaVac is a COVID-19 vaccine produced by [Sinovac Biotech](http://www.sinovac.com/index.php?lang=en), a China-based pharmaceutical company with headquarters in Beijing. The company focuses specifically on the development and manufacturing of vaccines to target human infectious diseases. This two-dose vaccine is recommended for individuals aged 18 years and above. It has an efficacy rate of [50\.4%](https://www.reuters.com/business/healthcare-pharmaceuticals/new-brazil-data-shows-disappointing-504-efficacy-chinas-coronavac-vaccine-2021-01-12/) for preventing symptomatic infection, according to data from a Brazilian trial, and an effectiveness of [67%](https://www.reuters.com/business/healthcare-pharmaceuticals/chinas-sinovac-covid-19-vaccine-67-effective-preventing-symptomatic-infection-2021-04-16/), according to a real-world study in Chile. Sinovac’s vaccine was validated for Emergency Use Listing (EUL) by the [WHO](https://www.who.int/news/item/01-06-2021-who-validates-sinovac-covid-19-vaccine-for-emergency-use-and-issues-interim-policy-recommendations) on June 1. WHO’s EUL procedure for CoronaVac included a review of the vaccine’s safety and efficacy, as well as “onsite inspections of the production facility.” The Strategic Advisory Group of Experts on Immunization (SAGE), WHO’s main advisory board regarding vaccines, also reviewed the vaccine as part of WHO’s EUL validation. As of January 2022, the vaccine is approved for use in [52 countries](https://covid19.trackvaccines.org/vaccines/7/). CoronaVac is an [inactivated vaccine](https://www.medicalnewstoday.com/articles/mnt-620130). It uses a dead version of the [SARS](https://www.medicalnewstoday.com/articles/7543)\-CoV-2 virus so that it cannot replicate, but it keeps the surface spike protein intact to trigger the body’s immune system to create antibodies for protection against the live virus, if it were to invade. ### Coronavirus resources For more advice on COVID-19 prevention and treatment, visit our [coronavirus hub](https://www.medicalnewstoday.com/coronavirus). ## [Common side effects]() Phase 1 and 2 clinical trial data for the vaccine, published in *[The Lancet](https://www.thelancet.com/article/S1473-3099\(20\)30843-4/fulltext)* in February 2021, reveal some of the side effects reported by trial participants. **According to the data, the most common side effect reported within 28 days of the second dose was injection-site pain (13–21%, depending on the dosing schedule). Injection site reactions are common with other COVID-19 vaccines, including the [two inactivated COVID-19 vaccines by Sinopharm](https://www.medicalnewstoday.com/articles/global-covid-19-vaccine-summary-side-effects#Currently-authorized-COVID-19-vaccines).** Other side effects included [fatigue](https://www.medicalnewstoday.com/articles/248002), [diarrhea](https://www.medicalnewstoday.com/articles/158634), and muscle pain. Most of these side effects were mild and lasted only for 2 days. Additionally, the paper notes that participants who received CoronaVac reported a lower occurrence of [fever](https://www.medicalnewstoday.com/articles/168266) in comparison to other COVID-19 vaccines, including the mRNA-based vaccine from [Moderna](https://www.medicalnewstoday.com/articles/moderna-covid-19-vaccine-what-to-know-about-side-effects) and viral vector vaccines from [Oxford-AstraZeneca](https://www.medicalnewstoday.com/articles/oxford-astrazeneca-vaccine-what-to-know-about-side-effects) and CanSino. ## [Who can receive the vaccine?]() Similar to other [COVID-19 vaccines approved by WHO](https://www.who.int/news-room/feature-stories/detail/the-sinovac-covid-19-vaccine-what-you-need-to-know), the global health agency recommends the CoronaVac vaccine for people with comorbidities, those who are immunocompromised, or those who previously have had COVID-19. The WHO also recommends CoronaVac for people living with [HIV](https://www.medicalnewstoday.com/articles/17131). It states that while the trials reviewed by SAGE did not include this specific population, CoronaVac is a nonreplicating vaccine and can be recommended. The WHO also notes that while this vaccine has not been sufficiently tested in pregnant people, its similarity to other vaccines deemed safe, such as those for [hepatitis B](https://www.medicalnewstoday.com/articles/306288), suggests that there are no expected concerns for the use of the vaccine during pregnancy. Until studies have adequately evaluated the safety of CoronaVac in pregnant individuals, the WHO recommends its use when the benefits of vaccination outweigh the potential risks. As with other authorized COVID-19 vaccines, individuals with a history of [anaphylaxis](https://www.medicalnewstoday.com/articles/216062) to any of the vaccine’s ingredients should not receive the vaccine. ## [Next steps in CoronaVac trials]() An [article](https://www.globaltimes.cn/page/202106/1225472.shtml) by the *Global Times* notes that, according to phase 2 clinical trials for the vaccine, a booster shot of CoronaVac after the initial two doses may boost antibody levels, with a tenfold increase in activity a week after the shot. Sinovac plans to continue its clinical trials to determine the efficacy and timing of the booster shot, as well as the vaccine’s effectiveness against emerging SARS-CoV-2 variants. Phase 3 clinical trial data for the vaccine will likely provide further insight into the efficacy and safety profile of the vaccine. ## [CoronaVac and Omicron]() Since experts named [Omicron](https://www.medicalnewstoday.com/articles/covid-19-why-the-omicron-variant-has-scientists-worried) a SARS-CoV-2 variant of concern, researchers have been looking into whether or not CoronaVac is effective against Omicron. A paper published in *[Nature Medicine](https://www.nature.com/articles/s41591-022-01705-6)* in January 2022 indicates that two doses of CoronaVac could not neutralize the Omicron variant. **“Notably, none of the individuals fully vaccinated with CoronaVac \[whose data the study analyzed\] had detectable neutralizing \[antibodies\] against \[the\] SARS-CoV-2 Omicron variant,” the paper authors write.** Adding a booster dose of the Pfizer-BioNTech mRNA vaccine somewhat improved the immune response to this variant. Still, participants had significantly reduced neutralization antibodies against Omicron compared with those produced against the Delta variant, suggesting a greater risk of vaccine breakthrough infections, the researchers warn. ***For live updates on the latest developments regarding the novel coronavirus and COVID-19, click [here](https://www.medicalnewstoday.com/articles/live-updates-coronavirus-covid-19).*** - [Public Health](https://www.medicalnewstoday.com/categories/public-health) - [Immune System / Vaccines](https://www.medicalnewstoday.com/categories/immune-system) - [Infectious Diseases / Bacteria / Viruses](https://www.medicalnewstoday.com/categories/infectious_diseases) - [COVID-19](https://www.medicalnewstoday.com/categories/covid-19) Share this article Written by Minseo Jeong — Fact checked by Harriet Pike, Ph.D. — [Updated on January 27, 2022]() ## Latest news - [9 steps to improve heart health, per new dietary guidance from AHA](https://www.medicalnewstoday.com/articles/9-steps-improve-heart-health-diet-guidance-aha) - [AI model can accurately predict liver cancer risk, study suggests](https://www.medicalnewstoday.com/articles/ai-model-accurately-predict-liver-cancer-risk) - [AI-powered stroke tool linked to improved patient outcomes in large clinical trial](https://www.medicalnewstoday.com/articles/ai-powered-stroke-tool-linked-improved-patient-outcomes-large-clinical-trial) - [Eating same meals on repeat, and more at weekends may help you lose more weight](https://www.medicalnewstoday.com/articles/eating-same-meals-repeat-more-weekends-may-help-lose-more-weight) - [Cooking at least one meal at home weekly may cut dementia risk by up to 67%](https://www.medicalnewstoday.com/articles/cooking-at-least-one-meal-at-home-weekly-may-cut-dementia-risk) ### Related Coverage - [Covaxin COVID-19 vaccine: What to know about side effects](https://www.medicalnewstoday.com/articles/covaxin-covid-19-vaccine-what-to-know-about-side-effects?utm_source=ReadNext) [In this Snapshot feature, we provide an overview of the Covaxin inactivated virus vaccine for COVID-19 and its possible side effects.](https://www.medicalnewstoday.com/articles/covaxin-covid-19-vaccine-what-to-know-about-side-effects?utm_source=ReadNext) [READ MORE](https://www.medicalnewstoday.com/articles/covaxin-covid-19-vaccine-what-to-know-about-side-effects?utm_source=ReadNext) - [Johnson & Johnson COVID-19 vaccine: What are the side effects?](https://www.medicalnewstoday.com/articles/johnson-johnson-covid-19-vaccine-what-are-the-side-effects?utm_source=ReadNext) [In this Spotlight feature, we offer an overview of the possible side effects of the Johnson & Johnson COVID-19 vaccine and discuss whether the vaccine…](https://www.medicalnewstoday.com/articles/johnson-johnson-covid-19-vaccine-what-are-the-side-effects?utm_source=ReadNext) [READ MORE](https://www.medicalnewstoday.com/articles/johnson-johnson-covid-19-vaccine-what-are-the-side-effects?utm_source=ReadNext) - [Oxford-AstraZeneca vaccine: What to know about side effects](https://www.medicalnewstoday.com/articles/oxford-astrazeneca-vaccine-what-to-know-about-side-effects?utm_source=ReadNext) [In this Snapshot, we take a closer look at the potential side effects associated with the Oxford-AstraZeneca COVID-19 vaccine, also known as Vaxzevria.](https://www.medicalnewstoday.com/articles/oxford-astrazeneca-vaccine-what-to-know-about-side-effects?utm_source=ReadNext) [READ MORE](https://www.medicalnewstoday.com/articles/oxford-astrazeneca-vaccine-what-to-know-about-side-effects?utm_source=ReadNext) - [Moderna COVID-19 vaccine: What to know about side effects](https://www.medicalnewstoday.com/articles/moderna-covid-19-vaccine-what-to-know-about-side-effects?utm_source=ReadNext) [In this feature, we highlight the most common side effects of the Moderna COVID-19 vaccine. We also explore how common they are and other safety…](https://www.medicalnewstoday.com/articles/moderna-covid-19-vaccine-what-to-know-about-side-effects?utm_source=ReadNext) [READ MORE](https://www.medicalnewstoday.com/articles/moderna-covid-19-vaccine-what-to-know-about-side-effects?utm_source=ReadNext) - [What is the Nipah virus and what is the risk of a global outbreak?](https://www.medicalnewstoday.com/articles/what-is-the-nipah-virus-and-what-is-the-risk-of-a-global-outbreak?utm_source=ReadNext) [Following the Nipah virus outbreak in India, we asked experts about ongoing research into treatments, if there is a cause for concern, and whether…](https://www.medicalnewstoday.com/articles/what-is-the-nipah-virus-and-what-is-the-risk-of-a-global-outbreak?utm_source=ReadNext) [READ MORE](https://www.medicalnewstoday.com/articles/what-is-the-nipah-virus-and-what-is-the-risk-of-a-global-outbreak?utm_source=ReadNext) © 2026 Healthline Media UK Ltd, London, UK. All rights reserved. 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This Snapshot article discusses the safety and side effects of CoronaVac, a COVID-19 vaccine that was recently validated by the World Health Organization (WHO) to protect against the SARS-CoV-2 virus. ![](https://i0.wp.com/post.medicalnewstoday.com/wp-content/uploads/sites/3/2021/06/GettyImages-1233312949_header-1024x575.jpg?w=1155&h=1528) [Share on Pinterest](https://www.pinterest.com/pin/create/button/?url=https%3A%2F%2Fwww.medicalnewstoday.com%2Farticles%2Fsinovac-covid-19-vaccine-what-are-the-side-effects&media=https%3A%2F%2Fpost.medicalnewstoday.com%2Fwp-content%2Fuploads%2Fsites%2F3%2F2021%2F06%2FGettyImages-1233312949_header-1024x575.jpg&description=Sinovac%20\(CoronaVac\)%20COVID-19%20vaccine%3A%20Safety%20and%20side%20effects "Share on Pinterest") What do we know about Sinovac’s COVID-19 vaccine, CoronaVac? Image credit: CHAIDEER MAHYUDDIN/Getty Images CoronaVac is a COVID-19 vaccine produced by [Sinovac Biotech](http://www.sinovac.com/index.php?lang=en), a China-based pharmaceutical company with headquarters in Beijing. The company focuses specifically on the development and manufacturing of vaccines to target human infectious diseases. This two-dose vaccine is recommended for individuals aged 18 years and above. It has an efficacy rate of [50\.4%](https://www.reuters.com/business/healthcare-pharmaceuticals/new-brazil-data-shows-disappointing-504-efficacy-chinas-coronavac-vaccine-2021-01-12/) for preventing symptomatic infection, according to data from a Brazilian trial, and an effectiveness of [67%](https://www.reuters.com/business/healthcare-pharmaceuticals/chinas-sinovac-covid-19-vaccine-67-effective-preventing-symptomatic-infection-2021-04-16/), according to a real-world study in Chile. Sinovac’s vaccine was validated for Emergency Use Listing (EUL) by the [WHO](https://www.who.int/news/item/01-06-2021-who-validates-sinovac-covid-19-vaccine-for-emergency-use-and-issues-interim-policy-recommendations) on June 1. WHO’s EUL procedure for CoronaVac included a review of the vaccine’s safety and efficacy, as well as “onsite inspections of the production facility.” The Strategic Advisory Group of Experts on Immunization (SAGE), WHO’s main advisory board regarding vaccines, also reviewed the vaccine as part of WHO’s EUL validation. As of January 2022, the vaccine is approved for use in [52 countries](https://covid19.trackvaccines.org/vaccines/7/). CoronaVac is an [inactivated vaccine](https://www.medicalnewstoday.com/articles/mnt-620130). It uses a dead version of the [SARS](https://www.medicalnewstoday.com/articles/7543)\-CoV-2 virus so that it cannot replicate, but it keeps the surface spike protein intact to trigger the body’s immune system to create antibodies for protection against the live virus, if it were to invade. ## Phase 1 and 2 clinical trial data for the vaccine, published in *[The Lancet](https://www.thelancet.com/article/S1473-3099\(20\)30843-4/fulltext)* in February 2021, reveal some of the side effects reported by trial participants. **According to the data, the most common side effect reported within 28 days of the second dose was injection-site pain (13–21%, depending on the dosing schedule). Injection site reactions are common with other COVID-19 vaccines, including the [two inactivated COVID-19 vaccines by Sinopharm](https://www.medicalnewstoday.com/articles/global-covid-19-vaccine-summary-side-effects#Currently-authorized-COVID-19-vaccines).** Other side effects included [fatigue](https://www.medicalnewstoday.com/articles/248002), [diarrhea](https://www.medicalnewstoday.com/articles/158634), and muscle pain. Most of these side effects were mild and lasted only for 2 days. Additionally, the paper notes that participants who received CoronaVac reported a lower occurrence of [fever](https://www.medicalnewstoday.com/articles/168266) in comparison to other COVID-19 vaccines, including the mRNA-based vaccine from [Moderna](https://www.medicalnewstoday.com/articles/moderna-covid-19-vaccine-what-to-know-about-side-effects) and viral vector vaccines from [Oxford-AstraZeneca](https://www.medicalnewstoday.com/articles/oxford-astrazeneca-vaccine-what-to-know-about-side-effects) and CanSino. ## Similar to other [COVID-19 vaccines approved by WHO](https://www.who.int/news-room/feature-stories/detail/the-sinovac-covid-19-vaccine-what-you-need-to-know), the global health agency recommends the CoronaVac vaccine for people with comorbidities, those who are immunocompromised, or those who previously have had COVID-19. The WHO also recommends CoronaVac for people living with [HIV](https://www.medicalnewstoday.com/articles/17131). It states that while the trials reviewed by SAGE did not include this specific population, CoronaVac is a nonreplicating vaccine and can be recommended. The WHO also notes that while this vaccine has not been sufficiently tested in pregnant people, its similarity to other vaccines deemed safe, such as those for [hepatitis B](https://www.medicalnewstoday.com/articles/306288), suggests that there are no expected concerns for the use of the vaccine during pregnancy. Until studies have adequately evaluated the safety of CoronaVac in pregnant individuals, the WHO recommends its use when the benefits of vaccination outweigh the potential risks. As with other authorized COVID-19 vaccines, individuals with a history of [anaphylaxis](https://www.medicalnewstoday.com/articles/216062) to any of the vaccine’s ingredients should not receive the vaccine. ## An [article](https://www.globaltimes.cn/page/202106/1225472.shtml) by the *Global Times* notes that, according to phase 2 clinical trials for the vaccine, a booster shot of CoronaVac after the initial two doses may boost antibody levels, with a tenfold increase in activity a week after the shot. Sinovac plans to continue its clinical trials to determine the efficacy and timing of the booster shot, as well as the vaccine’s effectiveness against emerging SARS-CoV-2 variants. Phase 3 clinical trial data for the vaccine will likely provide further insight into the efficacy and safety profile of the vaccine. ## Since experts named [Omicron](https://www.medicalnewstoday.com/articles/covid-19-why-the-omicron-variant-has-scientists-worried) a SARS-CoV-2 variant of concern, researchers have been looking into whether or not CoronaVac is effective against Omicron. A paper published in *[Nature Medicine](https://www.nature.com/articles/s41591-022-01705-6)* in January 2022 indicates that two doses of CoronaVac could not neutralize the Omicron variant. **“Notably, none of the individuals fully vaccinated with CoronaVac \[whose data the study analyzed\] had detectable neutralizing \[antibodies\] against \[the\] SARS-CoV-2 Omicron variant,” the paper authors write.** Adding a booster dose of the Pfizer-BioNTech mRNA vaccine somewhat improved the immune response to this variant. Still, participants had significantly reduced neutralization antibodies against Omicron compared with those produced against the Delta variant, suggesting a greater risk of vaccine breakthrough infections, the researchers warn. ***For live updates on the latest developments regarding the novel coronavirus and COVID-19, click [here](https://www.medicalnewstoday.com/articles/live-updates-coronavirus-covid-19).***

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