Address Concerns About Vaccine Side Effects
Serious adverse events are rare, but COVID-19 vaccines may be more reactogenic than other vaccines. For some vaccines that require two doses, side effects after the second dose may be more noticeable than those experienced after the first dose. Importantly, some people have no side effects at all. In a study conducted in the United Kingdom, 25% of people who received an mRNA vaccine reported experiencing a systemic side effect, and 66% had a local reaction. Women tend to report side effects more frequently than men do.
The Centers for Disease Control and Prevention (CDC) and the U.S. Food and Drug Administration continue to closely monitor several reporting systems:
CDC also provides timely updates on selected serious adverse events reported after COVID-19 vaccination.
- COVID-19 vaccines are safe and effective and severe reactions after vaccination are rare.
- Several expected short-term side effects associated with COVID-19 vaccines represent predictable vaccine reactions. These include injection-site reactions (e.g., pain, redness, swelling) and systemic reactions (e.g., tiredness, headache, muscle pain, chills, fever, nausea).
- Patients contemplating vaccination should know which side effects to expect and understand why they occur (i.e., these side effects are normal signs that the body is building protection).
- Serious adverse events after COVID-19 vaccination may occur, but they are rare. CDC is providing routine updates on the serious adverse events of interest, including anaphylaxis, thrombosis with thrombocytopenia syndrome, myocarditis and pericarditis, and Guillain-Barré syndrome.
- Delayed side effects from vaccines are extremely rare. Considering the dozens of vaccines developed over the last 100 years, vaccine-related side effects are almost always detected within 6 weeks after vaccination. Hundreds of millions of people have received COVID-19 vaccines in the United States alone. No long-term side effects have been detected. Nonetheless, safety surveillance continues.
Information for Pharmacy Teams
Information for Patients