Treat your partners right: Implication of sexual contact networks in partner management for sexually transmitted infections

Abstract

Sexually transmitted infections (STIs) have continued to increase among the heterosexual population and men who have sex with men (MSM) in the last five years. To better inform STI control strategies, the factors that influence the disease dynamics of STIs can be important to incorporate in developing infectious disease modeling for cost-effectiveness analysis. The spread of STIs depends on the macrostructure (e.g., random, clustered, scale-free networks) and microstructure (e.g., relationship dynamics) of the contact networks, and the sexual behaviors (e.g., condom use) commonly adopted in the population. In this thesis, we investigated different aspects that could influence STI transmission and the cost and effectiveness of STI control strategies in the population of interest. First, we evaluated how the structure of sexual contact network influences the cost and effectiveness of partner management strategies controlling for bacterial STIs in MSM. We found that the network structure, the compliance to intervention, and the resource constraint matter in determining the optimal partner management strategy. Second, we evaluated how relationship dynamics affects the cost-effectiveness of partner management strategies and quantified the value of key measures (concurrency and the average relationship duration) that inform relationship dynamics. We found that modeling sexual contact networks without measures informing relationship dynamics might lead to recommendation of a less cost-effective partner management strategy to control bacterial STIs, resulting societal loss. The value of collecting concurrency information is higher than the value of relationship duration. Third, we explored how HIV status disclosure, partner selection and condom use behavior changed with HIV prevalence in MSM using evolutionary game theory. We found that these behaviors varied with HIV prevalence. In particular, HIV-positive individuals were more likely to disclose their status and less likely to use condom at a high HIV prevalence than at a low HIV prevalence. These behavior changes should be considered in cost-effectiveness analysis to better inform interventions of HIV/STIs.