AIDS vaccine protects people, shocks researchers

(Agencies)
Updated: 2009-09-25 10:22

Sanofi shares rose as much as 1.6 percent in early trade in Paris but closed down slightly at 50 euros.

"We see no commercial vaccine available for some time yet, but the prospect has finally been raised (after 30 years of trying) that an effective vaccine is possible," said Michael Leacock, an analyst at ABN AMRO research.

"What is needed here is more in-depth analysis," Sanofi's Jim Tartaglia told a briefing. Dr. Donald Francis of Global Solutions for Infectious Diseases said the companies had limited amounts of vaccine left to test and would have to make more.

"For me the biggest question is, how do you take what we know of this vaccine and give it greater protective power. Once you know that, then it makes sense to go to other parts of a population," Sanofi's Chris Viehbacher told Reuters.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, which paid for most of the $105 million trial, said the team was confused because people who got the vaccine and who became infected anyway had just as much virus in their blood and just as much damage to their immune systems as HIV patients who went unvaccinated.

That meant the vaccine helped prevent infection but did nothing to affect the virus once it is in the body.

In addition, the immune responses that were generated by the vaccine should not, in theory, have protected anyone. Fauci said AIDS researchers may have to go back and see if they have been looking at the wrong things when checking the immune response to potential HIV vaccines.

Kim said the vaccine might not work in the people and places where HIV is most common -- in Africa, among men who have sex with men and among injecting drug users.

The vaccine was formulated specifically to work against two subtypes of the human immunodeficiency virus -- clade E, which circulates in Thailand and Southeast Asia, and clade B, common in the United States and Europe.

The volunteers in the trial got six shots over six months, four with ALVAC and two with AIDSVAX.

ALVAC is a genetically engineered canarypox virus that has spliced into it synthetic versions of three HIV genes. AIDSVAX is made using two versions of one HIV gene, one from the B subtype and one from the E subtype.

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