Syphilis is resurgent in the United States. The most striking epidemiological feature of the current epidemic is the disproportionate representation of men who have sex with men (MSM) among cases, with incidence also varying by geography and ethnicity. Cases of congenital syphilis have been increasing in recent years, as have rates in women, indicative of a changing epidemic. In particular, these trends suggest that the previously primarily MSM-focused epidemic has expanded into heterosexual populations.
Frequent screening of at-risk individuals remains the best available tool for syphilis control, but current public health efforts have not had the desired effect in reducing the disease burden. A risk-structured transmission model will be developed to characterize the epidemiology of syphilis in the United States and evaluate the potential impact of different approaches to syphilis screening on epidemic dynamics and the health of affected individuals. The model will incorporate both MSM and heterosexual populations. Given the importance that core group composition and geography will have on epidemic characteristics, and the resultant implications for sustaining syphilis control in these different contexts, this model will be fit to outbreaks in different jurisdictions.