The Centers for Disease Control & Prevention (CDC) released two scientific reports evaluating the effectiveness of the bivalent booster in nursing home residents. The
first study examined new COVID-19 cases each week, from November 2022 through early January 2023, in all U.S. nursing homes. The study found that
residents who were not up to date with the bivalent vaccine (but had been vaccinated or had a history of COVID-19) had 30-50 percent greater chance of developing COVID-19 compared to residents who were up to date. The
second study measured antibody levels in nursing home residents before and after the bivalent vaccine and tested how well their antibodies protected against different COVID-19 strains, including Omicron variants.
The bivalent booster resulted in a large increase in antibody levels that neutralized the Omicron variants, even in residents who had already had COVID-19 as well as 1 or 2 monovalent vaccines. These two studies provide evidence that the bivalent booster confers additional protection against the latest COVID-19 variants beyond prior infection and prior boosters.