HIV trial results an important step in vaccine development, UN says

With an estimated 42 million people living with HIV worldwide, the United Nations today said preliminary results of a large-scale trial of a candidate AIDS vaccine announced by a biotechnology company in the United States are an important step in developing an effective vaccine.

The World Health Organization (WHO) and the Joint UN Programme on HIV/AIDS (UNAIDS) said the trial by VaxGen using the AIDSVAX vaccine appears to show a protective effect among non-Caucasian populations, especially African Americans, although sample sizes were small. However, for the majority of the participants, who were Caucasians, the effect of the vaccine was minimal.

"These results are promising. The trial provides clear evidence that a vaccine can work," said Dr. Peter Piot, Executive Director of UNAIDS. "However, there is an urgent need for more targeted research to find out why the candidate vaccine only seems to work in certain population sub-groups."

The company stressed that the results announced today only represent findings from an initial analysis. The two UN agencies also stated that an effective vaccine providing widespread protection is still not on the horizon.

The AIDSVAX Phase III trial was the first large-scale human trial of an HIV vaccine, with over 5,400 volunteers from the United States, Canada, and the Netherlands, the majority of whom were men who have sex with men. The vaccine used in this trial was designed to reduce susceptibility to infection with HIV subtype B, which is prevalent in the Americas, Western Europe, Australia and New Zealand. One of the major challenges in HIV vaccine development is to develop one or multiple vaccines effective against all major subtypes of HIV.

"Continued HIV vaccine research remains an urgent global need," said Dr. Gro Harlem Brundtland, Director-General of WHO. "We will need many more trials to develop effective HIV vaccines, particularly against the most prevalent HIV sub-types which are having a devastating impact on populations in sub-Saharan Africa."