Evidence for transmission of SARS-CoV-2 at religious mass gatherings: A systematic review

Background: Transmission of SARS-CoV-2 at major mass gatherings (MGs) has been observed during the COVID-19 pandemic. Methods: In this systematic review done according to the PRISMA guidelines, PubMed and Scopus databases were searched for relevant studies to describe the epidemiology of SARS-CoV-2 in relation to major religious MGs including the Grand Magal of Touba (GMT), Hajj, Umrah, Kumbh Mela, Arbaeen and Lourdes pilgrimage during the COVID-19 pandemic. Results: Ten articles met the inclusion criteria and were included.No cases of SARS-CoV-2 were detected at 2020 and 2021 GMT or at the 2020 Hajj. In a small study, 7 % of tested individuals were positive after the 2022 GMT. SARS-CoV-2 prevalence during the 2021–2022 Hajj and Umrah seasons varied from 0 to 15 % in different studies. At the 2021 Kumbh Mela, 0.4 million COVID-19 cases were diagnosed among returning pilgrims across India and 1 % tested positive during a one-day survey conducted on participants. During the 2021 Arbaeen pilgrimage, 3 % pilgrims were tested positive. No relevant data were found in relation to SARS-CoV-2 transmission at the 2021 Arbaeen and Lourdes pilgrimages. Conclusion: The transmission of the SARS-CoV-2 virus during religious MG events depends on many factors such as: the number and density of pilgrims, the intensity of circulation of the virus in the hosting country and in countries sending international participants at the time of the event, the transmissibility of virus variants at the time of the event, the various preventive measures adopted, and the immune status of the pilgrims.