Reducing the Rates of Household Transmission: the Impact of COVID-19 Vaccination in Healthcare Workers with a Known Household Exposure.

Objective: To determine the impact of COVID-19 vaccination on infection rates in healthcare workers (HCWs) with a household exposure. Methods: Retrospective cohort study 8410 HCWs (400 fully vaccinated, 1645 partially vaccinated, 6365 unvaccinated), employed by a large integrated healthcare system in the southeastern United States, tested for SARS-CoV-2 between January 1 and February 26, 2021. Results: Benefit of vaccination persisted even with household exposure, with unvaccinated HCWs being 3.7 to 7.7 times more likely to be infected than partially or fully vaccinated HCW with positive household contacts respectively (partial OR = 3.73, 95% CI 2.17 - 6.47; full OR = 7.67, CI 2.75 - 21.35). Whereas 89.4% of unvaccinated COVID-positive HCWs with known household exposures were symptomatic, 50% of fully vaccinated HCWs had symptoms, reducing risk of secondary spread from and between HCWs. Conclusions: COVID-19 vaccination provided protection against infection even amongst healthcare workers with close household contact, and after adjusting for community prevalence. (c) 2022 Elsevier Ltd. All rights reserved.