Self-reported acute respiratory illness during the pre-ritual and post-return phases of Hajj among South African pilgrims in 2025: a retrospective cohort study.

Objectives: Respiratory illness is common during Hajj, but phase-specific data from sub-Saharan African pilgrims remain limited. We examined self-reported acute respiratory illness (ARI) among South African pilgrims during the pre-ritual period in Saudi Arabia and within 14 days after return and assessed associated factors. Methods: This retrospective observational cohort study included South African pilgrims accredited for the 2025 (1446H) Hajj. A structured electronic questionnaire was administered approximately 1 month after Hajj to capture symptoms retrospectively over two predefined recall periods. The primary outcome was modified syndromic ARI, defined as two or more self-reported symptoms from cough, subjective fever, sore throat, rhinorrhea, or nasal congestion during the relevant recall period. Logistic regression estimated unadjusted odds ratios and adjusted odds ratios (aORs) with 95% confidence intervals (CIs). Results: Of approximately 2500 accredited pilgrims, 541 (21.6%) completed the questionnaire. During the pre-ritual period, 234/541 reported modified syndromic ARI (43.3%; 95% CI 39.1-47.5). Pilgrims aged ≥60 years had lower adjusted odds of pre-ritual ARI than those aged 18-39 years (aOR 0.47; 95% CI 0.26-0.87). Seasonal influenza vaccination was associated with higher odds of pre-ritual ARI (aOR 1.57; 95% CI 1.10-2.26). Within 14 days after return, 257/541 reported ARI (47.5%; 95% CI 43.2-51.8). Pre-ritual ARI remained modestly associated with post-return ARI in exploratory adjusted analysis (aOR 1.46; 95% CI 1.03-2.07), while influenza vaccination was not associated with post-return ARI. Conclusions: Modified syndromic ARI was common before the core Hajj rites and after return. Findings should not be interpreted as influenza-like illness, coronavirus disease 2019, pathogen-confirmed infection, or influenza vaccine effectiveness.