Association of drug injection patterns with antibody to human immunodeficiency virus type 1 among intravenous drug users in Baltimore, Maryland.

During 1988 and 1989, intravenous drug users recruited through extensive community outreach efforts in Baltimore, Maryland, were interviewed about drug injection and sex practices in the prior 11 years, with screening for antibody to human immunodeficiency virus type 1 (HIV-1). Neither interviewers nor subjects were aware of HIV-1 serostatus until 2 weeks after the interview. Among 2,616 intravenous drug users who last injected drug within the same calendar year as screening, HIV-1 seroprevalence was 30.1% for those with any use of shooting galleries, 23.3% for those who shared needles but did not use shooting galleries, and 16.3% for drug users who denied both needle-sharing and gallery use between 1977 and 1987. Among 608 drug users who reported persistent use of shooting galleries since 1977 or subsequent initiation into drug use, there was a tendency for HIV-1 seroprevalence to increase with more recent onset of an injection career. Combined with a milder but similar tendency among 739 drug users who reported persistent sharing of needles, and a seroprevalence of 15.1% among participants who had just started injecting drugs in the 18 months prior to baseline, these data provide indirect evidence that a high risk for HIV-1 infection might occur early during a drug injection career.