An approach to quantifying the interaction between behavioural and transmission clusters: the case of Hepatitis C virus infections in HIV positive men who have sex with men

We hypothesize that patterns of sexual behaviour play a role in the conformation of transmission networks. If that was the case, behavioural grouping might in turn correlate with transmission networks and have the potential to predict proximity in viral phylogenies. To address this hypothesis, we present an intuitive approach for quantifying interactions between clusters of sexual behaviour along a virus phylogeny. Data from the Swiss HIV Cohort Study on condom use and incident Hepatitis C virus (HCV) sequences served as proof-of-concept. A strict inclusion criteria contrasting with relatively low HCV prevalence hindered our ability to identify significant relationships. This manuscript intends to serve as guide for studies aimed at characterizing interactions between behavioural patterns and transmission networks. Large transmission networks such as those of HIV or COVID-19 are prime candidates for applying this methodological approach.