efficacy of the vaccine product. The smaller the incidence of infection and/or the smaller the expected efficacy of the vaccine product, the larger the number of volunteers required. The efficacy is measured by comparing the rates of infection of individuals who received the product and those who received placebo. These trials last from 3 to 5 years and are very expensive. A high level of efficacy in Phase III does not guarantee effectiveness in controlling the epidemic. This must be assessed under the normal working conditions of the health system, which are different from the special conditions in which the effectiveness trials (Phase III) are conducted, when healthy volunteers are selected and receive the vaccine product or the placebo under highly controlled conditions. Effectiveness (Phase 1V trial) depends on the coverage, which is associated with the price of the products and the level of organization of the health services ( this level of trials assess the real life situation). 5. THE ETHICS OF HIV VACCINE RESEARCH It is critical to ensure the integrity of the human subjects of scientific research. Thus, the bodies responsible for clinical trials with HIV vaccine products in Zimbabwe must provide the best treatment proved anywhere in the world to those volunteers who may eventually become infected by HIV, ensure the safety and the protection of the human rights of the human subjects participating in research trials. All protocols pertaining to HIV vaccine research involving human subjects will be evaluated and guarantee human subject protection. The proposal should be reviewed and approved by the following bodies: 1. Research Council of Zimbabwe – whose role is to monitor and supervise potentially harmful research. This board also approves 15