PHA-Exch> AIDS vaccines experts confused and dismayed

[Claudio Schuftan]

From: Vern Weitzel <vern at coombs.anu.edu.au>
crossposted from: "[health-vn discussion group]" health-vn at cairo.anu.edu.au

http://www.enn.com/health/article/24369

From: By Maggie Fox, Health and Science Editor - Analysis
Published November 10, 2007 06:04 PM
AIDS vaccines experts confused and dismayed

WASHINGTON (Reuters) - AIDS vaccine researchers are worried about the future
of
their field after learning an experimental HIV vaccine not only does not
work,
but just might make recipients more susceptible to infection with the AIDS
virus.

They are worried about their volunteers and the future of AIDS vaccines in
general. And they are worried because they cannot understand how a vaccine
would
make a person more vulnerable.

Researchers from Merck & Co. (MRK.N: Quote, Profile, Research), which makes
the
vaccine, and the National Institute of Allergy and Infectious Diseases,
which is
helping develop it, said on Wednesday they believe a type of common cold
virus
used as the basis of the vaccine may somehow have made their volunteers more
susceptible to HIV.

They are meeting this week in Seattle to hash through the data and figure
out
what happened.

This is what they know: Out of 1,500 people vaccinated, 82 became infected
with
the AIDS virus. Of these, 49 got the vaccine and 33 got a placebo shot.

While they are counseling volunteers that they may have raised their own
risk of
becoming infected, they are also trying to figure out what happened.

"The data are disappointing and puzzling but we don't have definitive
answers,"
Dr. Lawrence Corey of Fred Hutchinson Cancer Research Center in Seattle, who
was
organizing the trial, told reporters.

Only one woman in the trial became infected with HIV. The rest were men
having
sex with other men, and it was the men who started out with the highest
immune
response to the adenovirus 5 common cold bug used to make the vaccine who
were
the most likely to become infected with the AIDS virus.

But the infected men were also less likely to have been circumcised --
circumcision can also prevent HIV infection -- and may have engaged in more
risky behavior. So did the vaccine actually do something, or were the
results a
fluke?
"I don't think we really do know," Dr. Keith Gottesdiener of Merck Research
Laboratories told Reuters.

FUTURE OF THE FIELD

Nearly 30 potential AIDS vaccines are being tested in people around the
world.
"It is very important for the future of the field," said Margaret Johnston,
director of the AIDS vaccine research program at the NIAID.

"It makes us rethink some of the candidates that are in trial," said Dr.
Seth
Berkley, president of the International AIDS Vaccine Initiative.
Even vaccine advocates are calling it a setback.

"These data are deeply disappointing and troubling, and raise more questions
than answers for the field of AIDS vaccine," said AIDS Vaccine Advocacy
Coalition executive director Mitchell Warren.

"This setback should not and can not diminish our commitment to developing
an
effective HIV vaccine," said NIAID director Dr. Anthony Fauci. "Every day,
another 12,000 people become infected with HIV, most of whom live in
resource-poor countries," he added.

The researchers agree the finding could at the very least scare people off
from
taking part in AIDS vaccine trials. And because HIV only infects people,
having
human volunteers is key to finding a way to prevent an infection that has
killed
25 million people and affects 40 million more.

"That is why we are being completely transparent, as open as possible,"
Fauci
said in a recent interview.

Berkley agreed. "I am only worried if there is a lot of buzz, misinformation
around," he said.

But the fact that vaccine volunteers even became infected drives home the
need
for a vaccine, said Berkley. All the volunteers were counseled about ways to
avoid HIV infection, and given condoms. "If those behavioral change
interventions worked, we wouldn't need a vaccine," Berkley said.

"People will get infected despite the best counseling possible."
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