HIV Incidence Rate Could be Rising Among San Francisco’s Male Injection Drug Users Who Have Sex With Men

The incidence of HIV infection may be increasing among intravenous drug users in San Francisco, according to a study in the Sept. 1 issue of the Journal of Acquired Immune Deficiency Syndromes, Reuters Health reports. Dr. Timothy Kellogg of the San Francisco Department of Public Health and colleagues conducted a retrospective study of 2,893 people who voluntarily underwent HIV testing more than once between 1993 and 1999 at San Francisco's county hospital or affiliated clinics. Eighty-four study participants contracted HIV over the six-year period (Reuters Health, 10/16). The majority of those who contracted HIV were injection drug users, with an incidence of 2.0 seroconversions per 100 person years. Overall HIV infection incidence rates were highest among male injection drug users who have sex with men (3.8 seroconversions per 100 person years). HIV incidence was lowest among non-injection drug users, heterosexual men and female non-injection drug users. The researchers write, "Overall, no temporal trend in annual HIV incidence was noted during the study period; however, HIV incidence among [male injection drug users who have sex with men] increased from 2.9 seroconversions per 100 person years in 1996 to 4.7 seroconversions per 100 person years in 1998." The researchers also noted that the rate of seroconversions recorded at the hospital and clinics was "unexpectedly high" and that HIV transmission among injection drug users "has not decreased over the last several years" (Kellogg et al., Journal of Acquired Immune Deficiency Syndromes, 9/1). In an interview with Reuters Health, Kellogg said, "We believe hospitals may provide a better sentinel surveillance setting for discovery of HIV seroconversion among injection drug users than traditional drug treatment centers, such as methadone clinics. Urban hospital populations include many IDUs who seek medical care of conditions relating to an active drug-using lifestyle" (Reuters Health, 10/16).