An important caveat to mention is that community structure in the sense used throughout this paper (i.e. measured as modularity Q ) does not take into account explicitly the extent to which communities overlap. Such overlap is likely to play an important role in infectious disease dynamics, because people are members of multiple, potentially overlapping communities (households, schools, workplaces etc.). A strong overlap would likely be reflected in lower overall values for Q; however, the exact effect of community overlap on infectious disease dynamics remains to be investigated.