Testing the pair-wise network model: Does it accurately predict the dynamics of STIs on a network?

Abstract

Background. Mathematical models are an essential tool in infectious disease epidemiology. The most fundamental, and still widely used mathematical model for looking at infectious diseases, is the simple SIS (susceptible-infected-susceptible) compartmental model. However, this type of model does not integrate the local contact network of individuals making them inappropriate for studying sexually transmitted infections (STIs). Goal. To evaluate the accuracy of the pair-wise network model, proposed by Eames & Keeling (2002), which incorporates the sexual contact network. Results. Compared to observed data, the predictions of the pair-wise model were a much better fit to the prevalence of chlamydia than those of the traditional simple SIS model. Conclusions. The results demonstrate the critical role of the network structure in the spread of chlamydia and other STIs. If decision-makers continue to rely on the simple SIS model, they could underestimate the effectiveness of prevention and control strategies, actually hindering our efforts to eliminate chlamydia. Also, good quality data on the sexual network structure of the target population is necessary in order to make accurate and useful predictions.