Silverman, Rachel A.Ceci, AlessandroCohen, AlasdairHelmick, MeaganShort, EricaBordwine, PaigeFriedlander, Michael J.Finkielstein, Carla V.2022-06-222022-06-222022-071080-6040http://hdl.handle.net/10919/110891In April 2021, a COVID-19 outbreak occurred at a correctional facility in rural Virginia, USA. Eighty-four infections were identified among 854 incarcerated persons by facilitywide testing with reverse transcription quantitative PCR (qRT-PCR). We used whole-genome sequencing to link all infections to 2 employees infected with the B.1.1.7α (UK) variant. The relative risk comparing unvaccinated to fully vaccinated persons (mRNA-1273 [Moderna, https:// www.moderna.com]) was 7.8 (95% CI 4.8–12.7), corresponding to a vaccine effectiveness of 87.1% (95% CI 79.0%–92.1%). Average qRT-PCR cycle threshold values were lower, suggesting higher viral loads, among unvaccinated infected than vaccinated cases for the N, E, and S genes. Vaccination was highly effective at preventing SARS-CoV-2 infection in this high-risk setting. This approach can be applied to similar settings to estimate vaccine effectiveness as variants emerge to guide public health strategies during the ongoing pandemic.Pages 1313-1320application/pdfenPublic Domain (U.S.)Article - Refereed2022-06-22https://doi.org/10.3201/eid2807.220091287Silverman, Rachel [0000-0003-3082-9664]1080-6059