Effectiveness of COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Frontline Workers Before and During B.1.617.2 (Delta) Variant Predominance — Eight U.S. Locations, December 2020–August 2021 | MMWR
Description
For frontline workers, COVID-19 mRNA vaccines, Pfizer-BioNTech and Moderna, are effective against viral infection, but less effective during Delta variant spread.