Compliance with the Use of Medical and Cloth Masks Among Healthcare Workers in Vietnam

Compliance rates for both medical and cloth masks decreased during the 4 weeks: medical mask use decreased from 77 to 68% (P < 0.001) and cloth masks from 78 to 69% (P < 0.001). The presence of adverse events (adjusted RR 0.90, 95% CI 0.85–0.95), and performing aerosol-generating procedures (adjusted RR 0.78, 95% CI 0.73–0.82) were negatively associated with compliance, while contact with febrile respiratory illness patients was positively associated (adjusted RR 1.14, 95% CI 1.07–1.20). Being compliant with medical or cloth masks use (average use ≥70% of working time) was not associated with clinical respiratory illness, influenza-like illness, and laboratory-confirmed viral infection.