Severe Acute Respiratory Coronavirus Virus 2 (Sars-Cov-2) Outbreaks in Nursing Homes Involving Residents Who Had Completed a Primary Coronavirus Disease 2019 (COVID-19) Vaccine Series-13 US Jurisdictions, July-November 2021.

Among nursing home outbreaks of coronavirus disease 2019 (COVID-19) with ≥3 breakthrough infections when the predominant severe acute respiratory coronavirus virus 2 (SARS-CoV-2) variant circulating was the SARS-CoV-2 δ (delta) variant, fully vaccinated residents were 28% less likely to be infected than were unvaccinated residents. Once infected, they had approximately half the risk for all-cause hospitalization and all-cause death compared with unvaccinated infected residents.