COVID-19 Vaccines are Effective
CDC is reviewing this page to align with updated guidance.
- COVID-19 vaccines are safe and effective.
- COVID-19 vaccination helps protect adults and children ages 6 months and older from getting severely ill with COVID-19 and helps protect those around them.
- Some people who are vaccinated against COVID-19 will still get sick and have a vaccine breakthrough infection because no vaccine is 100% effective.
Vaccine effectiveness is a measure of how well vaccination protects people against outcomes such as infection, symptomatic illness, hospitalization, and death. Vaccine effectiveness is typically measured through observational studies specifically designed to estimate individual protection from vaccination under “real-world” conditions.
Data on Vaccine Effectiveness and Vaccine Breakthrough Infections
As part of CDC’s ongoing efforts to understand how well COVID-19 vaccines are working, CDC is monitoring vaccine effectiveness and rates of breakthrough infections, hospitalizations, and deaths.