To date, evidence from clinical trials shows that the Pfizer-BioNTech and Moderna COVID-19 vaccines are safe and well-tolerated. The majority of side effects were mild or moderate and went away in one to two days.
Is there anyone who should not get the vaccine?
When you are deciding whether or not to get the COVID-19 vaccine, consider talking to your primary care physician or other provider if you have a history of severe allergic reactions to any substance, if you have a condition that compromises your immune system, if you are pregnant or breastfeeding, if you have a bleeding disorder, or if you have other specific questions.
Some participants in the COVID-19 vaccine studies have experienced mild or moderate side effects. The most common side effects are:
- Pain at the injection site (arm muscle where shot is given)
- Redness and swelling at the injection site
- Muscle pain
- Joint pain
Additional Safety & Side Effect FAQs
How do we know if a vaccine is safe, and how do we put together a list of side effects?
The same clinical trials, or studies, that determine effectiveness of vaccines are used to determine if the vaccine is safe for use. Volunteers in the vaccine studies are watched closely for side effects, which are also called adverse events. Researchers track all side effects, from mild to more serious, and report their findings.
Why do side effects occur?
Side effects are typically a sign that a vaccine is working!
How? The immune system is designed to protect the body from pathogens, or germs, like viruses. When you feel sick, you are actually feeling the effects of your body's immune response to an "invader."
Vaccines "teach" the immune system how to fight off these invaders. When your body is learning how to protect you, you may feel symptoms similar to the symptoms of the illness—although they are typically much milder. This means that if you are exposed to an actual pathogen, like the coronavirus, your body will know what to do to keep you from getting sick.