title: A nice day for an infection? Weather conditions and social contact patterns relevant to influenza transmission.
abstract: Although there is no doubt that significant morbidity and mortality occur during annual influenza epidemics, the role of contextual circumstances, which catalyze seasonal influenza transmission, remains unclear. Weather conditions are believed to affect virus survival, efficiency of transmission and host immunity, but seasonality may also be driven by a tendency of people to congregate indoors during periods of bad weather. To test this hypothesis, we combined data from a social contact survey in Belgium with local weather data. In the absence of a previous in-depth weather impact analysis of social contact patterns, we explored the possibilities and identified pitfalls. We found general dominance of day-type (weekend, holiday, working day) over weather conditions, but nonetheless observed an increase in long duration contacts ([Formula: see text]1 hour) on regular workdays with low temperatures, almost no precipitation and low absolute humidity of the air. Interestingly, these conditions are often assumed to be beneficial for virus survival and transmission. Further research is needed to establish the impact of the weather on social contacts. We recommend that future studies sample over a broad spectrum of weather conditions and day types and include a sufficiently large proportion of holiday periods and weekends.
authors.affiliation: Center for Health Economics Research & Modeling of Infectious Diseases, Center for the Evaluation of Vaccinations, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium. lander.willem@ua.ac.be
authors.forename: Lander
authors.initials: L
authors.lastname: Willem
authors.forename: Kim
authors.initials: K
authors.lastname: Van Kerckhove
authors.forename: Dennis L
authors.initials: DL
authors.lastname: Chao
authors.forename: Niel
authors.initials: N
authors.lastname: Hens
authors.forename: Philippe
authors.initials: P
authors.lastname: Beutels
mesh_terms: D006801:Humans; D007251:Influenza, Human / Q000635:transmission*; D007398:Interpersonal Relations; D012621:Seasons; D012919:Social Behavior; D014887:Weather