Background The Johns Hopkins Hospital Emergency Department ((JHHED) has served as an observational window on the HIV-epidemic. We previously reported that HIV prevalence decreased among patients attending JHHED from 11.4% in 2003 to 5.6% in 2013 and incidence decreased from 0.99% in 2003 to 0.16%. This study sought to examine the potential contribution of changes in sexual and parenteral risk behaviour during this period by examining trends in HSV-2 and HCV infection in this population.

Methods Identity unlinked-serosurveys were conducted in the adult JHHED in 2003, 2007, and 2013. Excess sera collected from 10,274 patients were tested for HSV-2 and HCV antibodies by the Focus HerpeSelect and Genedia HCV 3.0 ELISA.

Results HSV-2 seroprevalence was 55.3% in 2003, 54.4% in 2007, and 50.0% in 2013 (p-trend = 0.296) and there were no significant changes when stratified by age group. HSV-2 seroprevalence among HIV positives also remained stable at 79.8% in 2003, 79.6% in 2007, and 78.3% in 2013 (p-trend = 0.660). In contrast, HCV seroprevalence declined steadily from 22.0% in 2003 to 13.8% in 2013. This was also consistent with a decrease in HCV seroprevalence among HIV positives: 59.6% in 2003, 53.6% in 2007, and 48.1% in 2013 (p-trend = 0.011). Black men had the highest change in HIV prevalence from 20.0% in 2003 to 9.9% in 2013, which correlated with changes in HCV seroprevalence in black men from 36.7% in 2003 to 22.1% in 2013. HSV-2 seroprevalence in black men remained stable between 2003 (53.3%) and 2013 (50.6%).

Conclusions The decline of HIV prevalence and incidence in the JHHED population is not likely attributable to changes in sexual behaviour since HSV-2 age-based prevalence remained unchanged over 10 year period. Rather the declines in HIV may be due to reductions in parental transmission with the observed parallel declines in HCV prevalence.

Disclosure of interest statement The authors have no conflicts of interest to declare.