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NLM AIDSLINE
Feasibility of an HIV-1 vaccine efficacy trial among injecting drug users (IDUs) in Bangkok, Thailand.
Vaniyapongs T; Kampanartsanyakorn C; Vanichseni S; Apaiwongse O; Raktham
January 30, 1997
Int Conf AIDS. 1996 Jul 7-12;11(2):34 (abstract no. We.C.214). Unique

Issues In 1988, prevalence of HIV-1 infection among Bangkok IDUs in treatment increased from 1% to 40%. Despite available interventions, HIV transmission continues at an alarming rate. In response to this epidemic, efforts are underway to establish cohorts of persons at high risk for HIV infection for possible HIV-1 vaccine efficacy trials. Project Development of baseline information and an infrastructure that could be used to conduct a phase III HIV-1 vaccine efficacy trial. Results Despite drug treatment and other education and intervention programs for IDUs in Bangkok, retrospective and cross sectional studies in 1991-93 estimated an HIV-1 incidence rate of about 10% per year. Incident HIV-1 infection was associated with needle sharing, incarceration, and being single. While the initial epidemic among IDUs was primarily due to HIV-1 subtype B, by 1994, 20% of infections were due to subtype E, which is responsible for the larger heterosexual epidemic in Thailand. Of an estimated 40,000 active IDUs in Bangkok, the BMA annually enrolls about 8,000 individual IDUs into a network of 15 drug treatment clinics, primarily offering methadone detoxification. In 1995, a phase I/II rgp 120 MN HIV-1 vaccine trial was conducted among 33 recovering IDUs in Bangkok. Also in 1995, among 1600 IDUs screened, willingness to participate in a prospective cohort study was high (83%); 500 HIV-negative IDUs were enrolled into such a study; and successful follow up at 4 months was 90%. Conclusions More than 4,000 HIV-negative IDUs at high risk for HIV-1 infection are accessible through drug treatment clinics of the BMA. An ongoing prospective cohort study will assess rates of successful follow up and HIV-1 incidence and will allow for the characterization of infecting HIV strains. This setting may allow for efficacy evaluation of HIV vaccines against the B and E subtypes of HIV-1.

*HIV-1/DRUG EFFECTS *Substance Abuse, Intravenous

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