Respiratory symptoms, vaccination coverage, and antibiotic use among Hajj pilgrims: a multi-season cross sectional...

Respiratory tract infections are the most frequently reported illnesses during Hajj, one of the world's largest recurring mass gatherings. The convergence of millions of pilgrims from diverse geographic regions in Makkah, Saudi Arabia creates conditions conducive to the transmission of respiratory pathogens. Understanding patterns of infection, vaccination coverage, and antibiotic use across multiple seasons is essential to inform preventive strategies.

A multi-season cross-sectional study was conducted during three consecutive Hajj seasons (2023-2025). Adult pilgrims were recruited and interviewed using a standardized structured questionnaire. Data collected included sociodemographic characteristics, vaccination history (meningococcal, influenza, COVID-19, pneumococcal), comorbidities, smoking behavior, respiratory symptoms, healthcare-seeking behavior, and antibiotic use. Multivariable logistic regression analyses were performed to identify factors independently associated with respiratory symptoms and antibiotic consumption.

A total of 712 human participants (adult Hajj pilgrims) were enrolled. Overall, 38.9% reported at least one respiratory symptom at the time of assessment, with cough (28.1%), sore throat (23.5%), and runny nose (21.9%) being most common. Chronic lung disease (adjusted odds ratio [aOR] 2.36; 95% CI 1.42-3.92), presence of ≥1 chronic condition (aOR 1.58; 95% CI 1.12-2.24), and current smoking (aOR 1.74; 95% CI 1.15-2.63) were independently associated with respiratory symptoms. Influenza vaccination was associated with reduced odds of multi-symptom respiratory illness (aOR 0.72; 95% CI 0.53-0.98). Among symptomatic participants, 29.6% reported antibiotic use, frequently in the absence of febrile illness. Vaccination coverage was high for meningococcal vaccine (96.1%), while pneumococcal vaccination coverage remained lower.

Respiratory symptoms remain a substantial health burden among Hajj pilgrims across consecutive seasons. Chronic lung disease and smoking increase susceptibility, while influenza vaccination appears protective. The frequent use of antibiotics highlights the need for strengthened antimicrobial stewardship. Enhanced vaccination uptake, targeted risk communication, and integrated prevention strategies are critical to mitigating respiratory infection risks during mass gatherings and safeguarding global public health.