Global meta-analysis of short-term associations between ambient temperature and pathogen-specific respiratory infections, 2004 to 2023.

BackgroundAmbient temperature may affect respiratory health, while the temperature sensitivity of respiratory infections may be pathogen-dependent.AimsWe sought to explore pathogen-specific associations between ambient temperature and respiratory infections.MethodsWe searched nine databases for a random-effects meta-analysis to pool the relative risk (RR) of respiratory infection by pathogen per 1° C temperature rise, compared to populations unexposed to the same temperature. We conducted pathogen-specific analyses, sensitivity analyses, subgroup analyses and meta-regression.ResultsA total of 137 studies were eligible for meta-analysis. The pooled and single-study estimates revealed that the incidence of respiratory syncytial virus (RR = 0.14; 95% confidence interval (CI): 0.09-0.23), influenza virus (IV) (RR = 0.40; 95% CI: 0.27-0.61), human metapneumovirus (RR = 0.48; 95% CI: 0.32-0.73), human coronavirus (HCoV) (RR = 0.21; 95% CI: 0.07-0.61) and SARS-CoV-2 (RR = 0.52; 95% CI: 0.35-0.78) decreased per 1° C temperature rise, while that of human parainfluenza virus (HPIV) (RR = 2.35; 95% CI: 1.46-3.77), human bocavirus (HBoV) (RR = 1.86; 95% CI: 1.04-3.32) and MERS-CoV (RR = 1.05; 95% CI: 1.04-1.07) increased. The risk of infection was lower for IVA, IVB, HCoV-229E and HCoV-OC43, while HPIV-3, and HBoV-1 were at increased risk. The risk of Streptococcus pyogenes pharyngitis (RR = 0.46; 95% CI: 0.30-0.69) decreased per 1° C temperature rise, while Pseudomonas aeruginosa (RR = 1.04; 95% CI: 1.03-1.05) and Legionella pneumophila infections (RR = 2.69; 95% CI: 1.11-6.53) increased.ConclusionsTemperature sensitivity of respiratory infections can vary with the specific pathogen type and subtype that causes the infection. As the climatic conditions will become warmer, public health policy makers should act to develop pathogen adaptation strategies.