Incidence, risk factors, and whole-genome sequence of SARs-CoV-2 and influenza virus among the Egyptian pilgrims returning from Umrah mass gathering in Saudi Arabia, April-May 2022

Abstract

Background: Ramadan Umrah is the second largest Islamic pilgrimage with 2.75 million pilgrims allowed in 2022. This report presents the results of a survey among Egyptian pilgrims returning from Ramadan Umrah to monitor SARS-CoV-2 and influenza activity and identify prevalent SARS-CoV-2 variants after this mass gathering.

Methods: Cross-sectional survey conducted at Cairo airport from 30th April 2022-5 th May 2022. Pilgrims were invited to participate voluntarily. After consenting, participants interviewed using questionnaire including demographics, health status, and vaccination information and asked to provide NP/OP swabs for SARS-CoV-2 and influenza testing by RT-PCR. Whole-genome sequencing performed for 29 SARS-CoV-2 isolates. Incidence calculated, descriptive data analysis performed, and SARS-CoV-2 patients were compared to negatively tested participants using chi² and p value< 0.05.

Results: Overall, 1003 subjects participated, their mean age 50.9 ± 13 years, 594 (59.2%) were males. Of them, 76(7.6%) tested positive including 67(6.7%) SARS-CoV-2, 7(0.7%) influenza and 2(0.2%) SARS-CoV-2/influenza coinfection. Omicron sublineage BA.2 was the prevalent variant with no difference in severity identified between BA.1 and BA.2. No difference was identified between COVID-19 incidence among receivers of different vaccine types or between fully vaccinated and booster dose receivers.

Conclusions: Survey indicated a low incidence of SARs-CoV-2 and influenza among Egyptian pilgrims returning from Ramadan Umrah. Patients had mild or no symptoms with no hospitalization or deaths reported. Full vaccination and booster doses of COVID-19 vaccines proved equally effective. Enhancing COVID-19 and influenza vaccination before mass gatherings and close monitoring of respiratory viruses among pilgrims returning from Hajj and Umrah are crucial for outbreak early detection and mitigation.

Keywords: COVID-19; Egypt; Incidence; Influenza virus; SARS-CoV-2; Umrah pilgrims; Whole-genome sequencing.