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Emerg Infect Dis
. 2022 Jul;28(7):1313-1320.
doi: 10.3201/eid2807.220091.
Vaccine Effectiveness during Outbreak of COVID-19 Alpha (B.1.1.7) Variant in Men's Correctional Facility, United States
Rachel A Silverman, Alessandro Ceci, Alasdair Cohen, Meagan Helmick, Erica Short, Paige Bordwine, Michael J Friedlander, Carla V Finkielstein
- PMID: 35731137
- DOI: 10.3201/eid2807.220091
Abstract
In 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.modernatx.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 nucleocapsid, envelope, and spike 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.
Keywords: COVID-19; SARS-CoV-2; United States; correctional facilities; incarcerated persons; prisons; respiratory infections; severe acute respiratory syndrome coronavirus 2; vaccine effectiveness; viruses; zoonoses.