Population-Level Benefits of Extragenital Gonorrhea Screening among Men Who Have Sex with Men: An Exploratory Modeling Analysis.

BACKGROUND: Men who have sex with men (MSM) are disproportionately burdened by gonorrhea and face high rates of extragenital (rectal and pharyngeal) infection, which is mostly asymptomatic and often missed by urogenital-only screening. Extragenital screening likely remains below CDC-recommended levels. Since increasing screening coverage is often resource-intensive, we assessed whether improved extragenital screening among men already presenting at clinics could lead to substantial reductions in prevalence and incidence. METHODS: We calibrated an agent-based model of site- and race-specific gonorrhea infection in MSM to explicitly model multi-site infection within an individual and transmission via anal, orogenital, and ororectal sex. Compared to current screening levels, we assessed the impact of increasing screening at 1) both extragenital sites, 2) only the rectal site, and 3) only the pharyngeal site among men already being urogenitally screened. RESULTS: All scenarios reduced prevalence and incidence, with improved screening at both extragenital sites having the largest effect across outcomes. Extragenitally screening 100% of men being urogenitally screened reduced site-specific prevalence by an average of 42% (black MSM) and 50% (white MSM), with these values dropping by approximately 10% and 20% for each race group when targeting only the rectum and only the pharynx, respectively. However, increasing only rectal screening was more efficient in terms of the number of screens needed to avert an infection as this avoided duplicative screens due to rectum/pharynx multi-site infection. CONCLUSIONS: Improved extragenital screening substantially reduced site-specific gonorrhea prevalence and incidence, with strategies aimed at increasing rectal screening proving the most efficient.