Prevalence of Influenza Among Hajj Pilgrims: A Systematic Review and Meta-Analysis.

OBJECTIVES Respiratory transmission, especially in mass gatherings, is considered one of the main ways of influenza transmission. The Hajj ceremony, as one of the largest gatherings worldwide, can increase the distribution of influenza infection. Thus, the present study aimed to evaluate the incidence of influenza among Hajj pilgrims. METHODS In this present systematic review and meta-analysis, all English studies published by 2019 were extracted from several databases such as the Web of Science, PubMed, Scopus, Cochrane Library, Science Direct, and Google Scholar. Finally, the data were extracted using a pre-prepared checklist and then analyzed by fixed and random effects model tests in the meta-analysis, Cochran, meta-regression, and Begg's test. RESULTS Eighteen studies with a sample size of 62 431 were entered into the meta-analysis process. The overall prevalence of influenza, in addition to the prevalence of types A, B, and C influenza, was estimated at 5.9 (95% CI: 4.3-8.0), 3.6 (95% CI: 2.6-4.9), 2.9 (95% CI: 2.8-3.1), and 0.9% (95% CI: 0.5-1.5), respectively. CONCLUSIONS In general, influenza remains widespread regardless of vaccinating pilgrims and following health protocols. Therefore, it is recommended that comprehensive management and educational approaches be used to reduce the prevalence of influenza and its adverse consequences among the pilgrims.