Official Hopes to Explain AIDS Vaccine Disparities

National Institutes of Allergy and Infectious Diseases Director Dr. Anthony S. Fauci said his institute plans to perform laboratory tests on Aidsvax trial volunteers' blood samples to uncover factors that might account for the vaccine's being more effective among African Americans and non-Hispanic minorities than for other subjects. But Fauci said he would first consult a number of statisticians to try to determine whether the possible protective benefits among minorities from the VaxGen vaccine represented a statistical fluke or some unexpected biological or behavioral factor.

The possible benefit involved a small subset of minority participants -- nearly 500 of 5,400 volunteers -- and was an unexpected finding. "The statistics look impressive," Fauci said. But Fauci and other AIDS and vaccine experts urged caution, stressing that the possible benefit was based on preliminary statistical analyses.

Fauci said the findings were "provocative enough to give very good reason to consider funding a larger study of this or other AIDS vaccines among minorities," if statisticians agree that they would be worthwhile. His team, Fauci said, would test cells in the participants' blood for specific HLA antigens, which can indicate whether a person is more susceptible to certain infections or less likely to respond to certain vaccines. He said they would also test the cells to see how they responded after being exposed to components of viruses. VaxGen researchers said they would test the vaccine recipients' blood samples and compare the antibodies of the infected subjects versus uninfected subjects. The identification of antibodies that protect against infection might help vaccine development.

Black AIDS Institute Executive Director Phill Wilson said, "However promising this vaccine may look for black people, it is a promise for tomorrow. The possibility of a vaccine that works only for African Americans should jump-start black America's involvement in the vaccine development and approval process."

Dr. José Esparza, the UN's top AIDS vaccine expert, asked, "Would this vaccine work in Africa?" Esparza added, "we cannot take the wrong tack, believing this is just racial, when in fact it could be something else, and we have not identified it yet."

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