Based on these data, I compare the predicted and simulated infectiousness of households in Fig. 2 , which shows the average over all households sizes and compares this to the final analytical approximation given by equation (31) for b * (t * ), and also the alternate approximation which considers all secondary infections to arise in the second generation of infection ; the simulations and the first approximation are clearly in good agreement. Individual based stochastic simulations were programmed using Berkeley Madonna, and are described in Appendix S1.