Frequency of Correct Mask Use Among Pedestrians in High-Flow Indoor Public Spaces: A Multicenter Analysis in the First and Second Waves of the COVID-19 Pandemic in Peru

Background: Our study aimed to describe the variation in the frequency of correct mask use among pedestrians in the first and second waves of the COVID-19 pandemic in high-flow indoor public spaces from different geographic and social settings in Peru. Methods: We carried out a cross-sectional exploratory study among pedestrians in Lima (the capital city) and other coastal and highland cities in Peru. Pedestrians were directly observed by trained medical students in 2 high-flow indoor areas at different times in November 2020 (first wave) and October 2021 (second wave). Primary outcomes included the frequencies of mask use and correct use. We applied multinomial logistic models and estimated crude and adjusted relative prevalence ratios for sex, age, obesity, and location. Additionally, we used binomial generalized linear models to estimate prevalence ratios in crude and adjusted models. Results: We included 1996 participants. The frequency of mask use was similar in both years: 96.9% in 2020 and 95.5% in 2021. However, the frequency of correct mask use significantly decreased from 81.9% (95% CI, 79.4-84.3) in 2020 to 60.3% (95% CI, 57.2-67.3) in 2021. In 2020, we observed an increase in the probability of misuse in the cities of Lima (aRP: 1.42; P =.021) and Chiclayo (aPR: 1.62, P =.001), whereas, in 2021, we noted an increase in the probability of misuse in the cities of Lima (aRP: 1.72; P <.001) and Piura (aPR: 1.44; P <.001). Conclusions: The correct mask use decreased during the second wave, although no significant overall variations were observed in mask use in pedestrians between both periods. Also, we found regional differences in correct mask use in both periods.