COVID-19 case rates among students and staff in Los Angeles County transitional kindergarten through grade 12 (TK–12) schools remained low compared with the surrounding community.
For frontline workers, COVID-19 mRNA vaccines, Pfizer-BioNTech and Moderna, are effective against viral infection, but less effective during Delta variant spread.
COVID-19 vaccine effectiveness, reinfection, and hospitalization in fully, partially, and unvaccinated people during the Delta variant in Los Angeles County, California.
COVID-19 vaccine effectiveness against hospitalizations was stable, but it declined against new infections among adults in New York during May-July 2021.
COVID-19 vaccine effectiveness against hospitalizations was stable for people who received 2 doses, and vaccines remained effective among people with risk for severe COVID-19.
COVID-19 mRNA vaccines, Pfizer-BioNTech and Moderna, are effective against infection among nursing home residents, but effectiveness declined in recent months.