Background
Herpes simplex virus type II (HSV-2) infection increases both susceptibility to and transmissibility of HIV, and HSV-2 and HIV are often strongly associated in HIV epidemics. We assessed trends in HSV-2 prevalence among non-injecting drug users (NIDUs) when HIV prevalence declined from 16% to 8% among NIDUs in New York City.
Methods
Subjects were current non-injecting users of heroin and/or cocaine and who had never injected illicit drugs. 3157 NIDU subjects were recruited between 2005–2014 among persons entering Mount Sinai Beth Israel substance use treatment programs. Structured interviews, HIV and HSV-2 testing were administered. Change over time was assessed by comparing 2005–2010 to 2011–2014 time periods. HSV-2 incidence was estimated among persons who participated in multiple years.
Results
HSV-2 prevalence was strongly associated with HIV prevalence (OR=3.9, 95% CI 2.9–5.1) from 2005–2014. HSV-2 prevalence declined from 60% to 56% (p=0.01). The percentage of NIDUs with neither HSV-2 nor HIV infection increased from 37% to 43%, (p<0.001); the percentage with HSV-2/HIV co-infection declined from 13% to 6%, (p<0.001). Estimated HSV-2 incidence was 1 – 2/100 person-years at risk
Conclusions
There were parallel declines in HIV and HSV-2 among NIDUs in New York City from 2005 to 2014. The increase in the percentage of NIDUs with neither HSV-2 nor HIV infection, the decrease in the percentage with HSV-2/HIV co-infection, and the low to moderate HSV-2 incidence suggest some population-level protection against resurgence of HIV. Prevention efforts should be strengthened to end the combined HIV/HSV-2 epidemic among NIDUs in the city.