Examine the effect of a universal facemask policy for healthcare workers(HCW) and incidence of SARS-CoV-2 positivity.
Daily number of symptomatic HCW tested, SARS-CoV-2 positivity rates, and HCW job-descriptions were collected pre and post Universal HCW facemask policy(March 26). Multiple change point regression was used to model positive-test-rate data. SARS-CoV-2 testing and positivity rates were compared for pre-intervention, transition, post-intervention, and follow-up periods.
Between March 12-August 10, 2020, 19.2% of HCW were symptomatic for COVID-19 and underwent SARS-CoV-2 testing. A single change point was identified ∼March 28–30(95% probability). Before the change point, the odds of a tested HCW having a positive result doubled every 4.5-7.5 days. Post-change-point, the odds of a tested HCW having a positive result halved every 10.5–13.5 days.
Universal facemasks was associated with reducing HCW's risk of acquiring COVID-19.