SubSaharan Africa is presently the region of the world most severely affected by the global HIV/AIDS pandemic. Zimbabwe bears one of the heaviest burdens of HIV/AIDS in the world, with an estimated 25% of sexually-active adults being HIV positive. The epidemic's effects are already being felt, but the full impact is yet to come. Identification of effective, affordable and sustainable interventions is therefore an urgent public health priority.

Peer education offers a potentially powerful, affordable means of delivering health education messages to communities. By identifying members of the target group to serve as educators and condom distributors, communities are mobilized to help themselves. Because this approach relies on existing human resources rather than technology or extensive use of specialists, it is likely to be a relatively affordable and sustainable intervention. Despite the fact that peer education has been widely promoted, however, it has not been examined rigorously using a randomized trial or HIV infection as an end-point. For these reasons, the Zimbabwe AIDS Prevention Project (ZAPP) decided to undertake a randomized trial of peer education.

In 1993, ZAPP began enrolling men at 40 participating factories in Harare, Zimbabwe's capital city. Workers were eligible to enrol if they were 18 years or older and able to give consent to participation in the study. As participants, ZAPP enrollees agreed to answer a brief questionnaire and to undergo testing for syphilis, hepatitis B virus and HIV every six months. A ZAPP clinic was established to provide counselling, testing and STD treatment. Enrolment proceeded over a period of several years.

In June 1994, ZAPP offered 20 randomly selected factories a peer education intervention. Four factories declined to participate in peer education because of the time that would be involved, so four additional factories were selected from the comparison group. The nonpeer education factories continued to be offered counselling, testing and adequate condom supplies at six-monthly visits.

Peer educators were selected at each workplace and trained using a syllabus developed by the Matabeleland AIDS Council (MAC) and a teaching module from AMREF Tanzania. Training took place over one week and covered the role of the peer educator, the world HIV/AIDS epidemic, STD symptoms and treatment, HIV transmission, prevention and care. After the initial training, the peer educators met at sixmonth intervals to attend refresher courses.

The minimum peer educator goals were to: have one peer educator for every 100 workers, maintain a continuous supply of free condoms at work sites, and organize at least one drama and two presentations by persons living with HIV/AIDS (one man and one woman). Peer educators also led discussions, showed videos and slide shows.

A total of 2219 men were documented as being HIV negative after peer education was introduced; 78% completed at least one followup. The overall incidence of HIV infection was 2.52 per 100 person years. This is equivalent to 2.52%/year. When the time to HIV infection for all individuals enrolled in the cohort at "intervention" factories was plotted against the "control" factories, it showed that the peer education factories had fewer new HIV infections than the control factories. The difference was statistically significant.

Another behavioural intervention is voluntary counselling and testing for HIV. Counselling and testing were made available to all participants, whether or not they worked at a factory selected for peer education. Consequently, this study assessed the impact of peer education over and above the impact of counselling and testing for HIV, an intervention shown to contribute to behaviour change in other settings.

ZAPP's evaluation study has concluded that peerled health education with condom distribution and aggressive treatment of STDs should form the foundation of HIV prevention policy and the standard of care for the evaluation of further interventions in developing countries.