Association of a coronavirus disease 2019 (COVID-19) vaccine booster with control of a COVID-19 outbreak in a long-term care facility in Switzerland, November to December 2021.

Coronavirus disease 2019 (COVID-19) outbreaks in long-term care facilities are often correlated with high case fatality rates. We describe the association of administration of an mRNA booster with the control of an outbreak. Our findings highlight the possibility of vaccine booster early in an outbreak as a promising method to mitigate the spread of infection.