Sample size
SARS-CoV-2 infection
SARS-COV-2 INFECTION
Based on the scarce information available at the time of the design of the study, we assumed that the risk in HCWs of contracting COVID-19 was 30%. Furthermore, a 50% relative reduction in the incidence of SARS-CoV-2 infection was considered to be the minimum desirable for this intervention. For a 50% reduction, 95% confidence (type 1 error, α = 0.05), 80% power, and with a potential loss to follow-up of 20%, it was estimated that 160 participants per arm were needed.