AIDS vaccine failure upsets researchers - Los Angeles Times

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" The two-decade search for an AIDS vaccine is in crisis after two

field tests of the most promising contender not only did not protect

people from the virus but may have put them at increased risk of

becoming infected ...

Numerous experts are questioning both the scientific premises and the

overall strategy of the nearly $500 million in AIDS vaccine research

funded annually by the U.S. government ...

" None of the products currently in the pipeline has any reasonable

chance of being effective in field trials, " Desrosiers, a

molecular geneticist at Harvard University, declared last month at an

AIDS conference in Boston. " We simply do not know at the present time

how to design a vaccine that will be effective against HIV. "

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AIDS vaccine failure upsets researchers

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After a promising AIDS vaccine backfires, the scientific community

questions the approach.

From the Washington Post

March 21, 2008

WASHINGTON -- The two-decade search for an AIDS vaccine is in crisis

after two field tests of the most promising contender not only did

not protect people from the virus but may have put them at increased

risk of becoming infected.

The trials, which enrolled volunteers on four continents, have

spurred intense scientific inquiry and unprecedented soul-searching

as researchers try to make sense of what happened and assess whether

they should have seen it coming.

Both field tests were halted in September, and seven other trials of

similarly designed AIDS vaccines have been either stopped or put off

indefinitely. Some may be modified, and others canceled outright.

Numerous experts are questioning both the scientific premises and the

overall strategy of the nearly $500 million in AIDS vaccine research

funded annually by the U.S. government.

" This is on the same level of catastrophe as the Challenger disaster "

for NASA, said Dr. Gallo, co-discoverer of the human

immunodeficiency virus, which causes AIDS, and head of the Institute

of Human Virology in Baltimore.

The two recently closed studies used the same vaccine, made from a

common respiratory virus called adenovirus type 5 that had been

crippled and then loaded with fragments of HIV. Both studies were

halted when it became clear that one, known as the Step study, was

futile and possibly harmful.

The results of the other vaccine trial, conducted in South Africa and

known as Phambili, were revealed last month and worsened the gloom.

Although the number of new HIV infections in that study was far

smaller than in Step -- and too few to draw firm conclusions from --

those results, too, hinted at a trend toward harm among vaccine recipients.

Many researchers are questioning the scientific premises on which all

those studies were based, and wondering, along with AIDS activists,

what effect this near-worst-case scenario might have on tests of

future vaccines.

The working hypothesis for what went wrong is that the vaccine

somehow primed the immune system to be more susceptible to HIV

infection, a scenario neither foreseen nor suggested by previous studies.

The National Institutes of Health, which funded the Step and Phambili

trials, is convening a meeting next week to reassess its AIDS vaccine

program. But some respected scientists have already reached a verdict.

" None of the products currently in the pipeline has any reasonable

chance of being effective in field trials, " Desrosiers, a

molecular geneticist at Harvard University, declared last month at an

AIDS conference in Boston. " We simply do not know at the present time

how to design a vaccine that will be effective against HIV. "