Different responses of influenza epidemic to weather factors among Shanghai, Hong Kong, and British Columbia

Xi Ling Wang, Lin Yang, Daihai He, Alice Py Chiu, Kwok Hung Chan, King Pan Chan, Maigeng Zhou, Chit Ming Wong, Qing Guo, Wenbiao Hu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

29 Citations (Scopus)


Weather factors have long been considered as key sources for regional heterogeneity of influenza seasonal patterns. As influenza peaks coincide with both high and low temperature in subtropical cities, weather factors may nonlinearly or interactively affect influenza activity. This study aims to assess the nonlinear and interactive effects of weather factors with influenza activity and compare the responses of influenza epidemic to weather factors in two subtropical regions of southern China (Shanghai and Hong Kong) and one temperate province of Canada (British Columbia). Weekly data on influenza activity and weather factors (i.e., mean temperature and relative humidity (RH)) were obtained from pertinent government departments for the three regions. Absolute humidity (AH) was measured by vapor pressure (VP), which could be converted from temperature and RH. Generalized additive models were used to assess the exposure-response relationship between weather factors and influenza virus activity. Interactions of weather factors were further assessed by bivariate response models and stratification analyses. The exposure-response curves of temperature and VP, but not RH, were consistent among three regions/cities. Bivariate response model revealed a significant interactive effect between temperature (or VP) and RH (P < 0.05). Influenza peaked at low temperature or high temperature with high RH. Temperature and VP are important weather factors in developing a universal model to explain seasonal outbreaks of influenza. However, further research is needed to assess the association between weather factors and influenza activity in a wider context of social and environmental conditions.
Original languageEnglish
Pages (from-to)1043-1053
Number of pages11
JournalInternational Journal of Biometeorology
Issue number6
Publication statusPublished - 1 Jun 2017


  • Generalized additive model
  • Influenza
  • Interaction
  • Meteorology
  • Seasonality

ASJC Scopus subject areas

  • Ecology
  • Atmospheric Science
  • Health, Toxicology and Mutagenesis


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