HIV incidence among injection drug users in New York City, 1992-1997: evidence for a declining epidemic

We assessed recent (1992-1997) HIV incidence in the large HIV epidemic among injection drug users in New York City.

Data were compiled from 10 separate studies (N = 4979), including 6 cohort studies, 2 "repeat service user" studies, and 2 analyses of voluntary HIV testing and counseling services within drug treatment programs.

In the 10 studies, 52 seroconversions were found in 6344 person-years at risk. The observed incidence rates among the 10 studies were all within a narrow range, from 0 per 100 person-years at risk to 2.96 per 100 person-years at risk. In 9 of the 10 studies, the observed incidence rate was less than 2 per 100 person-years at risk. The weighted average incidence rate was 0.7 per 100 person-years at risk.

The recent incidence rate in New York City is quite low for a high-seroprevalence population of injection drug users. The very large HIV epidemic among injection drug users in New York City appears to have entered a "declining phase," characterized by low incidence and declining prevalence. The data suggest that very large high-seroprevalence HIV epidemics may be "reversed."