During clinical trials, vaccines are tested to ensure that the benefits of vaccination outweigh any potential side effects. Evidence from these clinical trials can help us learn about the most common side effects that can occur after vaccination.
What common side effects can occur after a vaccine?
The most common side effects after COVID-19 vaccination are mild and typically last 1-3 days, and include tiredness, redness or pain at the injection site, or a mild fever. Some people experience many side effects and some people don’t experience any side effects at all. Common side effects can vary depending on the vaccine.
What about serious side effects after vaccination?
While clinical trials identify common side effects, vaccines must continue to be monitored during vaccination campaigns to check for very rare side effects. These unusual side effects are often so rare that they might only happen in one out of millions, or even tens or hundreds of millions, of vaccine doses. Health authorities are constantly reviewing the evidence to ensure that the benefits of vaccination far outweigh the potential risk of rare adverse events.
As of May 2022, over 11.7 billion COVID-19 vaccine doses have been administered globally. Serious side effects are extremely rare.
If you have questions about what to expect after vaccination, including questions about common or rare side effects, it is a good idea to talk to a health care professional to learn more about the latest evidence.
Find out more about which countries have approved each COVID-19 vaccine. There are many approval pathways and these differ by country and regulatory authority. On our site, vaccines listed as approved include vaccines that have been approved, authorized, licensed, given emergency use authorization, given emergency approval, or made available for use via any mechanism recognized in that country. Consult the official health authority in each country to learn more about the process.