COVID-19 Vaccines are Effective Updated Dec. 23, 2021 Print COVID-19 vaccin

COVID-19 vaccines are safe and effective.

COVID-19 vaccination helps protect adults and children ages 5 years and older from getting sick or severely ill with COVID-19 and helps protect those around them.

Some people who are fully vaccinated against COVID-19 will still get sick and have a vaccine breakthrough infection because no vaccine is 100% effective.

COVID-19 Vaccines Work
How and Why CDC Monitors Vaccine Effectiveness

An illustrated image of two parents and a young child, all wearing masks, with the father holding a shield showing the word “vaccine” on the front.

Vaccine Effectiveness

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.

COVID-19 Vaccine Effectiveness

Rates of COVID-19 Cases and Deaths by Vaccination Status

Hospitalizations by Vaccination Status – COVID-NET

The Possibility of Getting COVID-19 after Vaccination: Breakthrough Infections