[Mask use during the COVID-19 pandemic in Brazil: results of the EPICOVID19-BR study].

By March 3, 2022, the COVID-19 pandemic has caused more than 399 million infections and claimed the lives of more than five million people worldwide. To reduce infection rates, a series of prevention measures indicated by the World Health Organization (WHO) were adopted by countries, including the use of masks. This study aims to describe mask use in Brazil via data analysis from the EPICOVID19-BR, a population-based study conducted in 133 cities in the country in four phases between March and August 2020. The proportion of individuals who reported wearing a mask when they left their homes was 97.9% (95%CI: 97.8-98.0). The interviewer did not see interviewees' mask in 50% (95%CI: 49.9-51.1) of the cases at the time of the interview. However, between phase one and four of the survey, we observed a 4.4% decrease in the proportion of interviewees who failed to wear masks at the time of the interview. Mask non-visualization was more prominent in women, participants aged 10-19 and 20-29 years of indigenous, black, and brown skin color, and those with elementary and high school education and in the Central-West Region. The use of cloth masks showed a 91.4% predominance (95%CI: 91.2-1.5) with a 4.9% increase between phases 1 and 4. The results of the study bring important information to reinforce COVID-19 control policies in Brazil. The high percentage of people who failed to wear masks at the time of the interview suggests that it is still important to reinforce prevention and self-care, rather than relating mask wear to a mandatory measure.