Current Issues in HIV Vaccine Development

An HIV preventive vaccine constitutes the best long-term hope to control the HIV/ AIDS pandemic. A number of scientific challenges must be addressed before a vaccine is developed. An important issue to be solved relates to the significance of the HIV genetic variability in terms of potential vaccine-induced protection. Since 1987 more than 30 different candidate vaccines have been tested in more than 6,000 healthy human volunteers. Most of these trials have been conducted in the United States and Europe, and also in developing countries. The first Phase III efficacy trials were initiated in 1998 and 1999 in the United States and Thailand, and the initial results will be available at the end of 2001. To accelerate vaccine development it is important to conduct multiple trials to simultaneously evaluate several types of vaccines, against different HIV subtypes, in diverse populations. Developing countries must strengthen their infrastructures to be able to conduct trials of the highest scientific and ethical standards.