Individual based simulations of influenza and smallpox pandemic spread and control, incorporating detailed information on population density, age structure, commuting patterns, workplace sizes and long-distance travel have highlighted the particular importance of the household as a fundamental unit of transmission [13, 14, 16, 17, 18] (and reviewed in [19] ). Pure household models have been used fruitfully to explore detailed policy options in a city-wide response to an influenza pandemic [20] . It thus seems a priori that household models are a natural starting point in terms of extending theory previously developed for the simplest assumption of homogeneous mixing.