Effectiveness of Face Mask for Prevention of Respiratory Tract Infection during Hajj: A Systematic Review and Meta-Analysis.

The Hajj is an annual mass gathering of people in Makkah, Saudi Arabia. Respiratory infections are common due to their potential for rapid spread in crowded settings. There is a lack of data regarding the effectiveness of face masks in preventing respiratory tract infections (RTIs), specifically during Hajj. We systematically searched PubMed, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials until July 3, 2023 for studies comparing the incidence or prevalence of RTIs in those who used any face mask during Hajj compared with no mask. Risk ratio (RRs) and 95% CIs were calculated using either a fixed or random-effect model, depending on the heterogeneity. A comprehensive analysis encompassed 10 studies involving 5007 participants. The overall RR favored wearing masks over not wearing masks regarding the incidence of RTIs; however, the difference was not statistically significant (RR = 0.78; 95% CI = 0.55-1.10; P = 0.16). A significantly lower incidence of RTIs was found in those wearing masks most of the time versus intermittently (RR = 0.59; 95% CI = [0.38-0.94; P = 0.02). In subgroup analyses, there was no difference between wearing masks and not wearing masks across different study designs (cohort/case-control), different groups (pilgrims/healthcare workers), and different years of Hajj, except from 2000 to 2008, when there was a significant difference favoring wearing face masks. This meta-analysis found wearing masks most of the time was associated with significantly lower risk of RTIs than wearing it intermittently.