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Factors associated with incarceration and incident human immunodeficiency virus (HIV) infection among injection drug users participating in an HIV vaccine trial in Bangkok, Thailand, 1999–2003


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    The Bangkok Vaccine Evaluation Group (BVEG): BVEG Coordinators—Kachit Choopanya (Principal Investigator), Suphak Vanichseni; The Bangkok Metropolitan Administration (BMA) Department of Health—Boonrawd Prasittipol, La-Ong Srisuwanvilai; BMA Department of Medical Services—Wonchat Subhachaturas, Udomsak Sangkum; Mahidol University—Valai Bussaratid, Jaranit Kaewkungwal, Dwip Kitayaporn, Sricharoen Migasena, Benjaluck Phonrat, Punnee Pitisuttithum, Sawangjai Pungpak, Pravan Suntharasamai; The Thailand Ministry of Public Health—U.S. Centers for Disease Control and Prevention Collaboration—Thanyanan Chaowanachan, Thitima Cherdtrakulkiat, Wanitchaya Kittikraisak, Wanna Leelawiwat, Michael Martin, Janet McNicholl, Supawadee Na-Pompet, Chalintorn Sinthuwattanawibul, Jordan W. Tappero, Frits van Griensven, Punneeporn Wasinrapee, Nancy Young; The U.S. Centers for Disease Control and Prevention—Dale Hu, Timothy D. Mastro; VaxGen, Inc.—Phillip Berman, Lisa Brooks, Marlene Chernow, Don Francis, Carolyn Gee, Marc Gurwith, William Heyward, Tina Ippolito, David Jobes, Tina Kalanon, Elizabeth Li, Aimee Luck, Karin Orelind, Patti Orozco-Cronin, Michael L. Peterson, Faruk Sinangil; Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center—Barbara Metch, Maggie Wang, and Michael Hudgens.

Michael Martin, Ministry of Public Health, Soi 4, DDC 7 Building, 4th Floor, Nonthaburi 11000, Thailand. E-mail:


Aims  To determine if incarceration was associated with human immunodeficiency virus (HIV) infection and identify risk factors for incarceration among injection drug users (IDUs) participating in an HIV vaccine trial in Bangkok.

Design  The AIDSVAX B/E HIV vaccine trial was a randomized, double-blind, placebo-controlled study. A proportional hazards model was used to evaluate demographic characteristics, risk behavior and incarceration as predictors of HIV infection and generalized estimation equation logistic regression analysis to investigate demographic characteristics and risk behaviors for predictors of incarceration.

Setting  The trial was conducted in Bangkok Metropolitan Administration drug-treatment clinics, 1999–2003.

Participants  A total of 2546 HIV-uninfected IDUs enrolled in the trial.

Measurements  HIV testing was performed and an interviewer-administered questionnaire was used to assess risk behavior and incarceration at baseline and every 6 months for a total of 36 months.

Findings  HIV incidence was 3.4 per 100 person-years [95% confidence interval (CI), 3.0–3.9] and did not differ among vaccine and placebo recipients. In multivariable analysis, being in jail (P < 0.04), injecting (P < 0.0001), injecting daily (P < 0.0001) and sharing needles (P = 0.02) were associated with HIV infection and methadone maintenance was protective (P = 0.0006). Predictors of incarceration in multivariable analysis included: male sex (P = 0.04), younger age (P < 0.0001), less education (P = 0.001) and being in jail (P < 0.0001) or prison (P < 0.0001) before enrollment.

Conclusions  Among IDUs in the AIDSVAX B/E trial, incarceration in jail was associated with incident HIV infection. IDUs in Thailand remain at high risk of HIV infection and additional prevention tools are needed urgently. HIV prevention services, including methadone, should be made available to IDUs.