The incidence of sexually transmitted infections (STIs) has increased dramatically over the last decade in Los Angeles County (LAC), with men-who-have-sex-with-men (MSM) bearing a disproportionate burden of disease. STIs are not only responsible for significant morbidity and potential long-term sequelae but strong evidence indicates STI infection promotes HIV transmission and acquisition among MSM. Given the relationship between STIs and HIV incidence, it follows that MSM who repeatedly contract STIs may disproportionately contribute to both STI and HIV transmission. Thus, understanding predictors of repeat STI infection is important for the development of targeted prevention efforts. Accordingly, Chapter 2 of this dissertation sought to identify the rate and socio-demographic predictors of repeat gonorrhea and/or chlamydia infection in a clinic-based population of predominantly men-who-have-sex-with-men (MSM) in Los Angeles County.

Given the rising rates of STIs among MSM identifying not only predictors of infection but effective methods of prevention is crucial for infection control. Modeling studies have indicated that increased testing frequency could significantly reduce transmission of HIV and quell the rise of STIs. However, despite its demonstrated value, STI testing rates among MSM remain extremely low. Conventional methods such as education and awareness campaigns have demonstrated limited success in prompting STI testing in MSM populations and thus it is important that innovative testing strategies are developed and their impact evaluated both in terms of clinical effectiveness and cost. As such, Chapter 3 of this dissertation evaluates the impact of an MSM-focused financial incentive program for STI and HIV testing on testing frequency and STI positivity. Chapter 4 assesses the cost-effectiveness of a financial incentive program to encourage MSM to undergo STI and HIV testing.