Contact network model of Karlsson et al. This section implements the contact network model of [Karlsson et al.](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC/), used to evaluate the efficacy of interventions aiming to control pneumococcal transmission. Individuals are assigned several features: an age, a household, and potentially a class in school/day care. These features then influence the rate of transmission between individuals in the population. Together this defines a stochastic process of the number of people infected. Reference [Karlsson et al. ()](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC/)