Des Jarlais DC, Kling R, Hammett TM, Ngu D, Liu W, Chen Y, et al. Reducing HIV infection among new injecting drug users in the China-Vietnam Cross Border Project. AIDS 2007 Dec;21 Suppl 8:S109-14.
To assess an HIV prevention program for injecting drug users (IDUs) using trends in HIV prevalence and estimated HIV incidence among new injectors in the cross-border area between China and Vietnam
Serial cross-sectional surveys with HIV testing of community-recruited IDUs' non-probability samples were conducted at baseline, at 6 months (during start-up), 12 months (during implementation) and 18, 24 and 36 months post-implementation.
Five sites in Lang Son Province, Vietnam and four sites in Ning Ming County, Guangxi Province, China between 2002 and 2005.
IDUs who reported injecting in the previous 6 months were eligible for repeated cross-sectional surveys with repeat participation permitted. New injectors were defined as having started injecting within 3 years of their current age. In Ning Ming County, snowball/peer recruitment was used and was initiated with a letter to individuals who were known to project peer educators as IDUs. In Lang Son Province, recruitment was from drug injecting sites and government registers. At baseline and at the subsequent five repeat surveys done every 6 months, the following number of IDUs was recruited, respectively, with the number of "new injectors" indicated in parentheses: In Ning Ming County; 235 (86), 260 (135), 249 (81) 265 (75) 183 (55), and 187 (25); In Lang Son Province, 190 (55), 190 (64), 176 (104), 181 (74), 180 (64) and 185 (55).
Detailed descriptions of the Cross Border Project have previously been described.(1) The project included outreach by peer educators and large-scale distribution of sterile injecting equipment at the five sites in Vietnam and the four sites in China. The intervention was adapted from a peer outreach model developed in the United States.(2)
During each wave, participants received HIV testing, along with pre- and post-test counseling, to determine HIV prevalence and to estimate HIV incidence in the community. A structured questionnaire was administered by trained interviewers to determine key demographics and injecting behaviors. Aside from the variations in the recruitment strategies, data collection methods were the same for all sites.
There were statistically significant declines in HIV prevalence and estimated HIV incidence among new injectors in these areas in China and Vietnam. HIV incidence declined in Ning Ming from 11 per 100 person-years at baseline to 0 (out of 25) at 36 months and declined in Lang Son from 20 per 100 person-years to 4 at 36 months. The percentage of new injectors among all subjects declined across each survey wave in both Ning Ming and Lang Son, although the decline was less uniform in Lang Son, and no analysis is offered of what role repeat participation might have played in this result at either site. There was relatively little variation in the mean number of years injecting in both areas. Because the number of new injectors declined, confidence intervals to estimate incidence are wider for the later time periods. In multivariate logistic regression, new injectors in later survey waves were less likely to be HIV infected after controlling for demographic characteristics. There were strong similarities in the associations of project implementation and the reduction in HIV prevalence and estimated incidence among new injectors in each area. Over the course of the project, an average of 10,000-15,000 new needles/syringes were provided each month in each country. In both areas, comparisons of pre-implementation survey results (baseline and 6-month) with the 24-month and 36-month survey results indicate reductions of approximately 50% and 75%, respectively, for prevalence and estimated incidence among new injectors.
The authors concluded that the implementation of large-scale peer outreach and distribution of sterile injecting equipment was followed by a substantial decrease in HIV infections among new injectors and no evidence of increase in the number of individuals who begin to inject drugs.
The quality of this study was limited by the following: 1. as individual subjects were permitted but not required to participate in each survey wave, changes between survey rounds may be attributable to factors unrelated to the intervention. In particular, no details are given about the number of repeat participants and whether those called new injectors remained new injectors in more than one survey; 2. participants were recruited using non-probability methods and results may not be generalizable; again, no information is offered on whether the same peers were used repeatedly to "seed" the snowball sampling in Ning Ming; 3. due to the study design, investigators were not able to assess the effect of potential causal factors and their interactions unrelated to the intervention, which could have contributed to the observed reductions in prevalence and estimated incidence among new injectors. Given these potentially serious limitations, the conclusions appear unqualified.
The high levels of HIV infection observed in the first two cross-sectional surveys are consistent with the rapid spread of HIV among IDUs in many industrialized and developing countries.(3) The dramatic reductions in estimated HIV incidence are similar to reductions in HIV incidence associated with large-scale expansion of risk reduction/prevention programs observed in many European and North American settings in the 1980s and 1990s.(4,5,6)
This project may serve as a model for large-scale HIV prevention programming for IDUs in China and Vietnam, as well as in other resource-limited settings. The design limitations of the surveys, however, suggest that one should be cautious about the study's conclusions.
- Cohen J. HIV and heroin: a deadly international affair. Science 2003;301:1657-58.
- Wiebel W. The indigenous leader outreach model: intervention manual. In: Levin L, editor. Rockville: National Institute on Drug Abuse; 1993. No abstract available.
- Stimson GV, Des Jarlais DC, Ball A, editors. Drug injecting and HIV infection: global dimensions and local responses. London: UCL Press; 1998. No abstract available.
- Des Jarlais DC, Friedman SR, Marmor M, Cohen H, Mildvan D, Yancovitz S, et al. Development of AIDS, HIV seroconversion, and potential co-factors for T4 cell loss in a cohort of intravenous drug users. AIDS 1987;1:105-11.
- van Haastrecht HJ, van den Hoek JA, Bardoux C, Leentvaar-Kuypers A, Coutinho RA. The course of the HIV epidemic among intravenous drug users in Amsterdam, the Netherlands. Am J Public Health 1991;81:59-62.
- Tyndall M, Johnston C, Craib K, Li K, Spittal P, O'Shaughnessy M, et al. HIV incidence and mortality among injection drug users in Vancouver - 1996-2000. Can J Infect Dis 2001;12:69B. Abstract not available.