A new Centers for Disease Control and Prevention study finds the mRNA COVID-19 vaccines authorized by the Food and Drug Administration, Pfizer-BioNTech and Moderna, reduce the risk of infection by 91% for fully vaccinated people.

This study is also among the first to show that mRNA vaccination benefits people who get COVID-19, despite being fully vaccinated or partially vaccinated.

“COVID-19 vaccines are a critical tool in overcoming this pandemic,” said CDC Director Rochelle P. Walensky. “Findings from the extended timeframe of this study add to accumulating evidence that mRNA COVID-19 vaccines are effective and should prevent most infections — but that fully vaccinated people who still get COVID-19 are likely to have milder, shorter illness and appear to be less likely to spread the virus to others. These benefits are another important reason to get vaccinated.”

The findings come from four weeks of additional data collected in CDC’s HEROES-RECOVER study of health care workers, first responders, front-line workers, and other essential workers. These groups are more likely to be exposed to the virus that causes COVID-19 because of their occupations. Preliminary results from this study were first announced in March 2021.

Read more about the study here.