Single Dose of an mRNA Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-Cov-2) Vaccine Is Associated With Lower Nasopharyngeal Viral Load Among Nursing Home Residents With Asymptomatic Coronavirus Disease 2019 (COVID-19)

In nursing home residents with asymptomatic COVID-19 diagnosed through twice-weekly surveillance testing, single-dose BNT162b2 vaccination (Pfizer-BioNTech) was associated with -2.4 mean log10 lower nasopharyngeal viral load than detected in absence of vaccination (P = .004). Since viral load is linked to transmission, single-dose mRNA SARS-CoV-2 vaccination may help control outbreaks.