Reported Adverse Events
Updated Sept. 12, 2023
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COVID-19 vaccine recommendations have been updated as of October 3, 2023 to add 2023-2024 updated Novavax COVID-19 vaccine. The content on this page will be updated to align with the new recommendations.
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At the April 19, 2023 meeting of the Advisory Committee on Immunization Practices, CDC
presented data related to further analyses of a preliminary safety signal for persons ages 65 years and older who received the updated (bivalent) Pfizer-BioNTech COVID-19 vaccine in one safety monitoring system, the Vaccine Safety Datalink (VSD). Other safety monitoring systems have not observed similar findings. As time has passed and more safety data have accumulated, the initial finding has decreased, and scientists believe factors other than vaccination might have contributed to the initial finding. The current evidence does not support the existence of a safety issue. FDA and CDC will continue to evaluate data as they are available and update the public as needed.
Safety of COVID-19 Vaccines
Some people have no side effects. Many people have reported side effects—such as headache, fatigue, and soreness at the injection site—that are generally mild to moderate and go away within a few days.
Are the Vaccines Safe?
What You Need to Know
- The benefits of COVID-19 vaccination continue to outweigh any potential risks.
- Severe reactions after COVID-19 vaccination are rare.
- CDC recommends everyone ages 6 months and older get vaccinated to protect against COVID-19 and its potentially severe complications.
- Millions of people in the United States have received COVID-19 vaccines under the most intense safety monitoring program in U.S. history.
- CDC, the U.S. Food and Drug Administration (FDA), and other federal agencies continue to monitor the safety of COVID-19 vaccines.
Anaphylaxis after COVID-19 Vaccination
Anaphylaxis after COVID-19 vaccination is rare. It has occurred at a rate of approximately 5 cases per one million vaccine doses administered. Anaphylaxis, a severe type of allergic reaction, can occur after any kind of vaccination. If it happens, healthcare providers can effectively and immediately treat the reaction. Learn more about COVID-19 vaccines and allergic reactions, including
anaphylaxis.
CDC scientists have conducted detailed reviews of cases of anaphylaxis and made the information available to healthcare providers and the public.
Scientific Publications about Anaphylaxis following COVID-19 Vaccination
Reports of Deaths after COVID-19 Vaccination
Multiple factors contribute to reports of death after COVID-19 vaccination, including heightened public awareness of COVID-19 vaccines, requirements under FDA authorization for COVID-19 vaccines that healthcare providers report any death after COVID-19 vaccination to VAERS (even if it is unclear whether the vaccine was the cause), and reporting requirements in CDC vaccine provider agreements. People receiving COVID-19 vaccines are less likely to die from COVID-19 and its complications
and are at no greater risk of death from non-COVID causes, than unvaccinated people.
CDC scientists and partners have performed detailed assessments of deaths after COVID-19 vaccination and made the information available to healthcare providers and the public.
Scientific Publications about Death following COVID-19 Vaccination
Guillain-Barré Syndrome (GBS) after COVID-19 Vaccination
GBS is a rare disorder in which the body’s immune system damages nerve cells, causing muscle weakness and sometimes paralysis. GBS has largely been observed among people ages 50 years and older.
Based on an analysis of data from the
Vaccine Safety Datalink (VSD), the rate of GBS within the first 21 days following J&J/Janssen COVID-19 vaccination was found to be 21 times higher than after Pfizer-BioNTech or Moderna (mRNA) COVID-19 vaccination. After the first 42 days, the rate of GBS was 11 times higher following J&J/Janssen COVID-19 vaccination. The analysis found no increased risk of GBS after Pfizer-BioNTech or Moderna vaccination.
Similarly,
CDC found higher than expected rates of GBS reported to VAERS after J&J/Janssen COVID-19 vaccination but not after mRNA COVID-19 vaccination. These observations contributed to the preferential recommendation by the Advisory Committee on Immunization Practices (ACIP) to use mRNA COVID-19 vaccines over the J&J/Janssen COVID-19 vaccine, which is no longer available in the United States.
CDC and FDA will continue to monitor for and evaluate reports of GBS occurring after COVID-19 vaccination and will share more information as it becomes available.
Myocarditis and Pericarditis after COVID-19 Vaccination
Myocarditis and pericarditis after COVID-19 vaccination are rare. Myocarditis is inflammation of the heart muscle, and pericarditis is inflammation of the outer lining of the heart. Most patients with myocarditis or pericarditis after COVID-19 vaccination responded well to medicine and rest and felt better quickly, and most cases have been reported after receiving mRNA COVID-19 vaccines.
To date, evidence indicates that
the benefits of mRNA COVID-19 vaccination outweigh the risk of myocarditis. CDC and FDA will continue to monitor for and evaluate reports of myocarditis and pericarditis after COVID-19 vaccination.
Learn more about myocarditis and pericarditis, including clinical considerations, after mRNA COVID-19 vaccination.
Data from VSD and from VAERS indicate that rates of myocarditis after COVID-19 vaccination are highest among males in their late teens and early 20s, usually following the second dose of the vaccine.
CDC scientists have conducted detailed reviews of cases of myocarditis and pericarditis after COVID-19 vaccines and have made the information available to healthcare providers and the public.