Decline in herpes simplex virus type 2 among non-injecting heroin and cocaine users in New York City, 2005 to 2014: Prospects for avoiding a resurgence of human immunodeficiency virus

Background: Herpes simplex virus type 2 (HSV-2) infection increases both susceptibility to and transmissibility of human immunodeficiency virus (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. Three thousand one hundred fifty-seven NIDU subjects were recruited between 2005 and 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 to 2010 with 2011 to 2014 periods. Herpes simplex virus type 2 incidence was estimated among persons who participated in multiple years. Results: Herpes simplex virus type 2 prevalence was strongly associated with HIV prevalence (odds ratio, 3.9; 95% confidence interval, 2.9-5.1) from 2005 to 2014. Herpes simplex virus type 2 prevalence declined from 60% to 56% (P = 0.01). The percentage of NIDUs with neither HSV-2 nor HIVinfection increased from37% to 43%, (P < 0.001); the percentagewith HSV-2/HIV coinfection declined from 13% to 6% (P < 0.001). Estimated HSV-2 incidence was 1 to 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 coinfection, 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 New York City.