AIDS breakthrough as vaccine cuts infections for first
time
BANGKOK (AFP) - – An experimental AIDS vaccine has for the first
time cut the risk of infection in humans in what scientists
Thursday called a "breakthrough" in the quarter-century fight
against the epidemic.
The vaccine reduced the chance of being infected by a third,
researchers announced after the world's largest trial of 16,000
volunteers, carried out by the US Army and Thailand's Ministry of
Public Health.
The surprising result comes after years of fruitless attempts by
the medical world to find an HIV vaccine, including one trial jab
that apparently boosted infection rates.
"It is the first demonstration that a vaccine against HIV can
protect against infection," Colonel Jerome Kim of the US military
HIV research programme told a news conference in Bangkok via
videolink.
"This is a very important scientific advance and gives us hope
that a globally effective vaccine may be possible in the future,"
he said.
Thai Public Health Minister Witthaya Kaewparadai said the
"outcome of this study is a scientific breakthrough."
The vaccine was a combination of two older drugs that had not
reduced infection on their own and the researchers said they were
now studying why the two apparently worked together.
The study combined the canarypox vaccine ALVAC, manufactured by
Sanofi-Aventis of France, and AIDSVAX, originally made by VaxGen
Inc and now licensed to the non-profit Global Solutions for
Infectious Diseases.
Researchers said the latest vaccine showed a 31.2 percent
efficacy in reducing the risk of HIV infection.
"The outcome represents a breakthrough in HIV vaccine
development because for the first time ever there is evidence that
HIV vaccine has preventative efficacy," said the research team in a
statement.
The vaccine was tested on volunteers -- all HIV negative men and
women aged from 18 to 30 -- at average risk of infection in two
Thai provinces near Bangkok starting in October 2003.
Half received the vaccine and the rest were given a placebo. Out
of the placebo recipients 74 of 8,198 became infected compared with
51 of 8,197 who got the vaccine.
The World Health Organization and the Joint UN Programme on
HIV/AIDS congratulated the researchers for the "encouraging"
results.
"The study results, representing a significant scientific
advance, are the first demonstration that a vaccine can prevent HIV
infection in a general adult population and are of great
importance," they said in a statement. Experts' reactions
The UN said it may not be possible to get licensing permission
for the drug at the moment based on the results, and that further
studies were needed to determine if the vaccine has the same effect
in other parts of the world.
AIDS first came to public notice in 1981 and has since killed at
least 25 million people worldwide, and 33 million others are living
with AIDS or the HIV virus.
Swift progress in identifying the virus that caused AIDS
unleashed early optimism that a vaccine would quickly emerge. HIV
destroys immune cells and exposes the body to opportunistic
disease.
But out of the 50 candidates that have been evaluated among
humans, only two vaccines have made it through all three phases of
trials, and both were flops. About 30 vaccines remain in the
pipeline.
Scientists were in 2007 forced to abandon two advanced clinical
trials of a vaccine by pharmaceutical company Merck after it
appeared to actually heighten the risk of AIDS infection.
Sanofi Pasteur, the vaccines division of Sanofi-Aventis, said
the results of the latest test, although "modest", were the first
concrete demonstration that a vaccine "could one day become a
reality."
The Global HIV Vaccine Enterprise, an alliance of researchers,
policymakers, donors and advocates that includes the Bill and
Melinda Gates Foundation, said it was a "historic day in the
26-year quest to develop an AIDS vaccine."
The International AIDS Vaccine Initiative (IAVI), an
organisation that promotes the search for a vaccine, said the trial
results were "very exciting and a significant scientific
achievement."
The head of the US agency tasked with controlling the spread of
infectious disease said it was an important breakthrough.
"These new findings represent an important step forward in HIV
vaccine research," said Anthony Fauci, director of the National
Institute of Allergy and Infectious Diseases (NIAID), part of the
US National Institutes of Health, which provided major funding and
logistical support for the study.
But a top AIDS scientist, France's Jean-Francois Delfraissy,
warned that the results were "good news but the effect remains
modest".