How effective is the COVID-19 vaccine?

Based on evidence from clinical trials, after two doses, the Pfizer-BioNTech vaccine was 95% effective* and the Moderna vaccine was 94.1% effective** at preventing COVID-19 in people without evidence of previous COVID-19 infection. The Johnson & Johnson’s Janssen vaccine was 66.3% effective in preventing COVID-19 after one dose.

*https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/Pfizer-BioNTech.html

**https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/Moderna.html