SIR Model for Households

SIAM Journal on Applied Mathematics, Volume 84, Issue 4, Page 1460-1481, August 2024.
Abstract. Households play an important role in disease dynamics. Many infections happen there due to the close contact, while mitigation measures mainly target the transmission between households. Therefore, one can see households as boosting the transmission depending on household size. To study the effect of household size and size distribution, we differentiated within and between household reproduction rates. There are basically no preventive measures, and thus the close contacts can boost the spread. We explicitly incorporated that typically only a fraction of all household members are infected. Thus, viewing the infection of a household of a given size as a splitting process generating a new small fully infected subhousehold and a remaining still susceptible subhousehold, we derive a compartmental ODE model for the dynamics of the subhouseholds. In this setting, the basic reproduction number as well as prevalence and the peak of an infection wave in a population with given household size distribution can be computed analytically. We compare numerical simulation results of this novel household ODE model with results from an agent-based model using data for realistic household size distributions of different countries. We find good agreement of both models showing the catalytic effect of large households on the overall disease dynamics.