Drug use and the risk of HIV infection amongst injection drug users participating in an HIV vaccine trial in Bangkok, 1999–2003☆☆☆
Received 8 October 2009; received in revised form 8 December 2009; accepted 15 December 2009. published online 15 January 2010.
Abstract
Background
HIV spread rapidly amongst injecting drug users (IDUs) in Bangkok in the late 1980s. In recent years, changes in the drugs injected by IDUs have been observed. We examined data from an HIV vaccine trial conducted amongst IDUs in Bangkok during 1999–2003 to describe drug injection practices, drugs injected, and determine if drug use choices altered the risk of incident HIV infection.
Methods
The AIDSVAX B/E HIV vaccine trial was a randomized, double-blind, placebo-controlled trial. At enrolment and every 6 months thereafter, HIV status and risk behaviour were assessed. A proportional hazards model was used to evaluate demographic characteristics, incarceration, drug injection practices, sexual activity, and drugs injected during follow-up as independent predictors of HIV infection.
Results
The proportion of participants injecting drugs, sharing needles, and injecting daily declined from baseline to month 36. Amongst participants who injected, the proportion injecting heroin declined (98.6–91.9%), whilst the proportions injecting methamphetamine (16.2–19.6%) and midazolam (9.9–31.9%) increased. HIV incidence was highest amongst participants injecting methamphetamine, 7.1 (95% CI, 5.4–9.2) per 100 person years. Injecting heroin and injecting methamphetamine were independently associated with incident HIV infection.
Conclusions
Amongst AIDSVAX B/E vaccine trial participants who injected drugs during follow-up, the proportion injecting heroin declined whilst the proportion injecting methamphetamine, midazolam, or combinations of these drugs increased. Controlling for heroin use and other risk factors, participants injecting methamphetamine were more likely to become HIV-infected than participants not injecting methamphetamine. Additional HIV prevention tools are urgently needed including tools that address methamphetamine use.
☆☆ Disclaimer: The findings and conclusions in this paper are those of the authors and do not necessarily represent the views of the U.S. Centers for Disease Control and Prevention.
1 The Bangkok Vaccine Evaluation Group—Kachit Choopanya (Principal Investigator), Suphak Vanichseni; The Bangkok Metropolitan Administration (BMA) Department of Health—Sithisat Chiamwongpaet, Wuwanee Raktham, Boonrawd Prasittipol, La-Ong Srisuwanvilai, Kovit Yongvanitjit; 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.
ABSTRACT