High genetic diversity of human rhinovirus among pilgrims with acute respiratory tract infections during the 2019 Hajj pilgrimage season

Detection of COVID-19 incidence among attendees of the 2022 Hajj season

Objectives

This study investigated the presence of COVID-19 cases among pilgrims, health care workers (HCWs), and non-HCWs of Hajj 2022.

Methods

Nasopharyngeal samples were collected from 491 attendees of Hajj 2022. All participants received three doses of COVID-19 vaccines. Paired (n = 138; 69 participants) and unpaired (n = 422; 422 participants) nasopharyngeal swabs were subjected to reverse transcription-polymerase chain reaction targeting E gene of β-coronaviruses and RNA-dependent RNA polymerase of SARS-CoV-2. The results were linked to the participants' profiles, including role during Hajj, presence of respiratory symptoms or comorbidities, contact with symptomatic individuals, smoking status, and COVID-19 recovery.

Results

A total of 20 (20 of 560; 3.6%) samples tested positive for COVID-19. Most cases (18 of 20; 90%) were pilgrims and non-HCWs. Six (30%) samples belonged to participants with previous positive reverse transcription-polymerase chain reaction. A total of 12 (60%) samples belonged to participants with respiratory symptoms. Three (15%) cases were linked to participants who had contact with individuals with respiratory symptoms. All cases belonged to individuals with no comorbidities, apart from a single case who has a chronic sinusitis. Five (25%) cases were smokers. No significant association was found between positive COVID-19 test and participants' profiles.

Conclusions

Few COVID-19 cases were detected in this study. Sustainable surveillance of COVID-19 and other respiratory viruses during Hajj seasons remains necessary.

Respiratory viral infections during Hajj seasons

Respiratory viral infections pose a public health concern during mass gathering (MG) events. Sustainable and continuous surveillance of respiratory viruses remains a priority to early identify and prevent potential outbreaks. This article reviews recent literature addressed the prevalence and diversity of circulating respiratory viruses during Hajj pilgrimage, one of the largest planned religious MG events held annually in Saudi Arabia. The variation between studies with respect to study design, sample size, time of sample collection (pre-, during, and pos-Hajj), type of participants (e.g., symptomatic vs. a symptomatic pilgrims), and laboratory procedure was highlighted. The majority of these studies were conducted on the 2019 Hajj season or earlier, prior to the emergence of COVID-19 which had significant impact on the past three Hajj seasons (2020, 2021, and 2022). A summary about key aspects related to organization of Hajj during COVID-19 pandemic and the implementation of exceptional infection control strategies is provided.

Genetic diversity and molecular analysis of human influenza virus among pilgrims during Hajj

The risk of transmission of respiratory tract infections is considerably enhanced at mass gathering (MG) religious events. Hajj is an annual Islamic MG event with approximately 3 million Muslim pilgrims from over 180 countries concentrated in Makkah, Saudi Arabia. This study aimed to investigate the genetic diversity of influenza viruses circulating among pilgrims during the Hajj pilgrimage. We performed a cross-sectional analytical study where nasopharyngeal swabs (NPs) from pilgrims with respiratory tract illnesses presenting to healthcare facilities during the 2019 Hajj were screened for influenza viruses. Influenza A subtypes and influenza B lineages were determined by multiplex RT-PCR for positive influenza samples. The phylogenetic analysis was carried out for the hemagglutination (HA) gene. Out of 185 nasopharyngeal samples, 54 were positive for the human influenza virus. Of these, 27 were influenza A H1N1 and 19 H3N2, 4 were untypable influenza A, and 4 were influenza B. Phylogenetic analysis revealed that the H1N1 and H3N2 strains differentiated into different and independent genetic groups and formed close clusters with selected strains of influenza viruses from various locations. To conclude, this study demonstrates a high genetic diversity of circulating influenza A subtypes among pilgrims during the Hajj Season. There is a need for further larger studies to investigate in-depth the genetic characteristics of influenza viruses and other respiratory viruses during Hajj seasons.

Epidemiological Differences in Hajj-Acquired Airborne Infections in Pilgrims Arriving from Low and Middle-Income versus High-Income Countries: A Systematised Review

This systematised review aims to compare the epidemiological patterns of Hajj-acquired airborne infections among pilgrims from low and middle-income countries (LMIC) versus those from high-income countries (HIC). A PubMed search was carried out for all published articles before February 2023, using a combination of MeSH terms and text words. The Newcastle-Ottawa Scale (NOS) was used to assess data quality. From a total of 453 titles identified, 58 studies were included in the review (LMIC = 32, and HIC = 26). In the pooled sample, there were 27,799 pilgrims aged 2 days to 105 years (male: female = 1.3:1) from LMIC and 70,865 pilgrims aged 2 months to 95 years (male: female = 1:1) from HIC. Pilgrims from both HIC and LMIC had viral and bacterial infections, but pilgrims from HIC tended to have higher attack rates of viral infections than their LMIC counterparts. However, the attack rates of bacterial infections were variable: for instance, pilgrims from LMIC seemed to have higher rates of meningococcal infections (0.015-82% in LMIC vs. 0.002-40% in HIC) based on the study population, but not Mycobacterium tuberculosis (0.7-20.3% in LMIC vs. 38% in HIC). Targeted measures are needed to prevent the spread of airborne infections at Hajj.