Washington - The writing had been on the wall for some time.
But last week, it became official.
The search for a vaccine against HIV, the virus that causes AIDS,
is taking an about-turn, back to the laboratory and away from human
trials that had held out so much hope in the past two years.
The news was delivered by Dr. Anthony Fauci, the man whose US
government institute controls about 80 per cent of the money spent
worldwide on vaccine research and testing.
It came just in time to add a sobering note to the international
AIDS community as it gathers for its biennial conference in Mexico
City from August 3 to 8 and grapples with the disappointing news.
Fauci, director of the US National Institute of Allergy and
Infectious Diseases (NIAID) who will attend the conference, explained
the decision in an interview with Deutsche Presse-Agentur dpa and
talked about 'bringing expectations down to realistic levels.'
We have to understand how difficult the situation is and not
expect that ... tomorrow we're going to start a large vaccine trial
and we're going to get the answer in a couple of years,' he told dpa.
'It is extremely unlikely that that will happen.'
Before the 2006 conference in Toronto, hopes soared for two
unconventional vaccines - the private Merck pharmaceuticals vaccine
as well as NIAID's own PAVE vaccine, which was very similar to the
Merck substance - as they headed into expanded clinical trials on
human beings.
But Merck dropped testing in September 2007, and Fauci pulled the
plug on the PAVE trials in mid July. The Merck vaccine was found
ineffective, and in fact appeared to have inadvertently increased the
HIV infection rate.
NIAID had backed development of the two unconventional vaccines
after two decades of frustration over the failure to find one that
worked along traditional lines.
The traditional approach to vaccines - using parts of the live
virus to induce antibodies and thus immunity on exposure, without
causing the illness - has not worked with HIV because the virus has
an astonishing ability to change and disguise itself from the body's
defences.
With HIV, the presence of antibodies does not protect against the
disease.
The PAVE and Merck vaccines attempted instead to cause a cellular
immune response that programmed the body's T-cells to search out and
kill virus-infected cells. The goal was to reduce the HIV count in
the body if the recipient became infected, slow down the progression
of the disease and reduce transmissibility from an infected person -
without expecting to totally eliminate the virus.
Fauci said the disappointing experiences with the alternative
vaccine demonstrated the need to 'rev up the burners' and return to
the laboratory to find how to create antibodies against the disease
without causing an actual infection.
That means less money will be spent on human trials of vaccines
that work in less conventional ways and more on animal testing, Fauci
said.
'It isn't that we're going to completely stop and turn around 180
degrees, but we're going to torque or turn the knob on the system
much more toward asking and answering some of the fundamental basic
questions that we have not been able to answer up to now,' Fauci
said.
The shift in focus follows intense discussion about downplaying
expectations within the AIDS research community. Scientists are even
annoyed by the rising pressure from the AIDS-affected community for
faster progress.
Seth Berkley, president and founder of the New York-based
International AIDS Vaccine Initiative (IAVI), cynically noted in the
Wall Street Journal recently that an AIDS vaccine would probably
materialize long before 'scientists discover a way to inoculate
against the kind of unrealistic expectations that have induced much
of the negative noise around the endeavour of late.'
Wayne Koff, a top IAVI researcher, told dpa that the field is
still 'in the early stages of vaccine development' and in the past
several years has gone through a 're-evaluation, a resetting of
expectations.' But he noted that the consortium searching for the
elusive antibody connection has immeasurably contributed to the
knowledge base.
Scientists have learned for example 'exactly where and how' the
antibodies attach onto the virus. Stimulating those antibodies to
neutralize the broad variety of viruses is the next step.
IAVI says the 700 million dollars spent worldwide on vaccine
research and testing every year is inadequate, and has been calling
for the sum to be pushed to 1 billion dollars.
USA
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