Spectrum of Respiratory Viruses Among Returning Iranian Pilgrims with Respiratory Symptoms During the COVID-19 Pandemic: A 2022 Study

The overcrowding conditions provide a favorable environment for viral transmission and increase the risk of respiratory infections among pilgrims. Hence, acute respiratory infections (ATIs) that can be transmitted through aerosols, droplets, and close contacts are a major public health concern during mass gathering (MG) events like Hajj. In this study, we reported the prevalence of different respiratory viruses in returning pilgrims at Tehran airport in August 2022 during the COVID-19 pandemic. In this cross-sectional study, throat and nasal swab samples from pilgrims with respiratory signs and symptoms were taken. The samples were sent to the National Influenza Center for influenza detection. We tested the samples for detection of influenza (IFV), SARS-CoV2, HCoV-229E, NL63, HKU1, OC43, human respiratory syncytial virus (HRSV), adenovirus (AdV), and human rhinovirus (HRV). Real-time RT-PCR was performed to detect all RNA viruses except HRV, and nested PCR was performed to detect AdV and HRV. Of returning pilgrims on arrival at Tehran airport, 10 (38.5%) were positive for at least one respiratory virus as follows: 2(7.7%) AdV, 3(11.5%) IFVA, which included 1 A/H1N1, 1 A/H3N2, and 1 A/H3N2 and A/H1N1 coinfection, 2 (7.7%) HCoV-229E, 2(7.7%) SARS-CoV2, 1(3.9%) HCoV-OC43, and 1(3.9%) HRV. No HRSV was detected. It is worth noting that the SARS-CoV2- positive sample was co-infected with IFVA/H3N2. This report showed that respiratory viruses remain a possible public health concern for pilgrims during Hajj seasons. We showed the circulation of some respiratory viruses among a small number of pilgrims during the COVID-19 pandemic.