Seasonal influenza epidemics vary in timing and size, but the causes of the variation remain unclear. Here, the authors analyse a 15-year city-level data set, and find that fluctuations in climatic factors do not predict onset timing, and that while antigenic change does not have a consistent effect on epidemic size, the timing of onset and heterosubtypic competition do.
- Edward K. S. Lam
- Dylan H. Morris
- Colin A. Russell
