First AIDS Vaccine: Better Than Nothing

By Alice Park

Ask AIDS experts, and they'll tell you the only way to control the epidemic is with a preventive vaccine. So why hasn't one been developed? It's not for lack of trying. Dozens of vaccines have worked in monkeys and against laboratory strains of HIV. But the virus mutates so quickly that no vaccine based on any particular strain is effective against them all.

Still, something may be better than nothing, and last week the Food and Drug Administration gave the go-ahead to test a less-than-perfect AIDS vaccine--the first approved for wide-scale human trials. The new vaccine, AIDSVAX, developed by a company based in San Francisco called VaxGen, contains snippets of two strains of HIV yet has proved safe. It will be tested on healthy but high-risk subjects--5,000 North Americans and then, if Thailand approves, 2,500 Thais. The trials will take at least four years to complete.

--By Alice Park