Declining seroprevalence in a very large HIV epidemic: Injecting drug users in new York city, 1991 to 1996

Objectives. This study assessed recent trends in HIV seroprevalence among i njecting drug users in New York City. Methods. We analyzed temporal trends in HIV seroprevalence from 1991 throug h 1996 in 5 studies of injecting drug users recruited from a detoxification program, a methadone maintenance program, research storefronts in the Lowe r East Side and Harlem areas, and a citywide network of sexually transmitte d disease clinics. A total of 11 334 serum samples were tested. Results. From 1991 through 1996, HIV seroprevalence declined substantially among subjects in all 5 studies: from 53% to 36% in the detoxification prog ram, from 45% to 29% in the methadone program, from 44% to 22% at the Lower East Side storefront, from 48% to 21% at the Harlem storefront, and from 3 0% to 21% in the sexually transmitted disease clinics tall P<.002 by chi(2) tests for trend). Conclusions. The reductions in HIV seroprevalence seen among injecting drug users in New York City from 1991 through 1996 indicate a new phase in this large HIV epidemic. Potential explanatory factors include the loss of HIV- seropositive individuals through disability and death and lower rates of ri sk behavior leading to low HIV incidence.