2.2.2. Preventing HIV infection

There are still few systematic reviews of the evidence on preventive interventions in the published literature. Merson et al. (2000) reviewed the effectiveness of projects and programmes in developing countries that aim to reduce sexual transmission of HIV infection or transmission related to injection drug use. They found that behavioural change interventions are effective when targeted to populations at high risk, particularly female sex workers and their clients. Few studies have evaluated harm reduction interventions in injecting drug users (IDUs). Evidence on the effectiveness of voluntary counselling and testing programmes was mixed, and results varied according to the population being studied. STI treatment appeared highly effective in reducing HIV/STI transmission, particularly in the earlier stages of the epidemic. Structural and environmental interventions show great promise, although more evaluation is needed. Merson et al. concluded that:

· HIV prevention interventions can be effective in changing risk behaviours and preventing transmission in low- and middle-income countries;

· when the appropriate mix of interventions is applied, they can lead to significant reductions in the prevalence of HIV at the national level; and

· additional research is needed to identify effective interventions, particularly in men who have sex with men, youth, IDUs and HIV -infected persons.

In practice, countries will strike a pragmatic balance, based on the capacity for programme implementation, the expected effects of interventions, their political feasibility and the availability of financial resources. For practical purposes, countries would need to consider interventions aimed at reducing risk and those aimed at reducing vulnerability (Table 1).

Table 1. Interventions for prevention of HIV infection