Childhood rotavirus infection associated with temperature and particulate matter 2.5 µm: A retrospective cohort study

No study has ever investigated how ambient temperature and PM_2.5 mediate rotavirus infection (RvI) in children. We used insurance claims data from Taiwan in 2006–2012 to evaluate the RvI characteristics in children aged ≤ 9. The RvI incidence rates were higher in colder months, reach-ing the highest in March (117.0/100 days), and then declining to the lowest in July (29.2/100 days). The age–sex-specific average incident cases were all higher in boys than in girls. Stratified analysis by temperature (<20, 20–24, and ≥25^◦C) and PM_2.5 (<17.5, 17.5–31.4, 31.5–41.9, and ≥42.0 µg/m³ ) showed that the highest incidence was 16.4/100 days at average temperatures of <20^◦C and PM_2.5 of 31.5–41.9 µg/m³, with Poisson regression analysis estimating an adjusted relative risk (aRR) of 1.26 (95% confidence interval (CI) = 1.11–1.43), compared to the incidence at the reference condition (<20^◦C and PM_2.5 < 17.5 µg/m³ ). As the temperature increased, the incident RvI cases reduced to 4.84 cases/100 days (aRR = 0.40, 95% CI = 0.35–0.45) when it was >25^◦C with PM_2.5 < 17.5 µg/m³, or to 9.84/100 days (aRR = 0.81, 95% CI = 0.77–0.93) when it was >25^◦C with PM_2.5 > 42 µg/m³ . The seasonal RvI is associated with frequent indoor personal contact among children in the cold months. The association with PM_2.5 could be an alternative assessment due to temperature inversion.