Measured Dynamic Social Contact Patterns Explain the Spread of H1N1v Influenza

Patterns of social mixing are key determinants of epidemic spread. Here we present the results of an internet-based social contact survey completed by a cohort of participants over 9,000 times between July 2009 and March 2010, during the 2009 H1N1v influenza epidemic. We quantify the changes in social contact patterns over time, finding that school children make 40% fewer contacts during holiday periods than during term time. We use these dynamically varying contact patterns to parameterise an age-structured model of influenza spread, capturing well the observed patterns of incidence; the changing contact patterns resulted in a fall of approximately 35% in the reproduction number of influenza during the holidays. This work illustrates the importance of including changing mixing patterns in epidemic models. We conclude that changes in contact patterns explain changes in disease incidence, and that the timing of school terms drove the 2009 H1N1v epidemic in the UK. Changes in social mixing patterns can be usefully measured through simple internet-based surveys.社交混合模式是传染病传播的核心决定因素。本研究展示了一项基于互联网的社交接触调查结果：在2009年甲型H1N1v流感（2009 H1N1v influenza）疫情期间，某参与者队列于2009年7月至2010年3月间累计完成该调查超9000次。研究量化了社交接触模式随时间的动态变化，发现学龄儿童在假期的接触频次较学期内降低40%。本研究利用这些随时间变化的接触模式，为流感传播的年龄结构模型完成参数化，该模型能够很好地拟合观测到的发病模式；同时，社交接触模式的变化使得假期期间流感的再生数下降约35%。本研究凸显了在传染病传播模型中纳入动态社交混合模式的重要性。我们得出结论：社交接触模式的变化能够解释疾病发病率的波动，而英国学校学期的时间安排是2009年甲型H1N1v流感疫情的关键驱动因素。通过简易的互联网调查，可有效量化社交混合模式的动态变化。