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BRIAN
DEER: THE VAXGEN EXPERIMENT Page 4
Every six
months, a ten-strong committee of doctors and
scientists crowds into VaxGen's boardroom. This is
the "data safety and monitoring board",
recruited to keep an eye on the experiment. On one
side of the table sits a Harvard infectious disease
specialist. On the other is a Yale ethicist. There
are three Thai physicians and a Seattle statistician.
Dr Walter Dowdle, a former CDC deputy director,
presides. The Americans are casual, in open-necked
shirts, but Dowdle runs proceedings with care. Piled
around the table are printouts on the volunteers,
with blood tests and other results. Using codes which
nobody else gets to look at, they can see who's
getting AidsVax and who the placebo and whether any
difference the number of HIV infections has emerged
between the groups.
By
the convention for vaccines, any difference would be
vast for the product to be declared effective.
Measles vaccine, for instance, is 95% effective,
tetanus 90%, and hepatitis B 85%. But the committee's
brief is to watch for just 30% effectiveness. Such is
the threat from Aids, it's argued, that this figure
is enough for success.
I
asked a professor of medical statistics to
number-crunch this percentage. To reach the 30% mark,
he said, there would only need to be 28 more
infections among junkies on the placebo than among
those receiving AidsVax. If VaxGen recruits 2,500 -
and on its assumption that in a year about 7% (87
people) on placebo will become infected due to
needle-sharing - then if the number who become
infected after getting AidsVax is 59 (4.7%) or fewer,
the committee can rule that the product works.
VaxGen
critics think that even this meagre difference
couldn't appear, and that Dowdle, 68, will one day
emerge to drape a consoling arm on Francis's
shoulder. But an alternative scenario is predicted by
some with long research experience. Nobody can recall
an HIV product being ditched after reaching a
full-scale efficacy trial. And, such is the desire
for "something to be done" about Aids that
science could be pushed to one side.
The
most powerful pressure for something to be done comes
from the White House, anxious to appease the Aids
lobby. In May 1997, President Clinton threw his
weight behind urgent action. "If the 21st
century is to be the century of biology," he
declared. "Let us make an Aids vaccine its first
great triumph."
How
such pressures can translate date back to 1989 and
the first anti-Aids drug, AZT. A board like Dowdle's
monitoring a trial among HIV-positive volunteers with
no obvious illness, saw data suggesting that
full-blown Aids could be prevented. At the time, AZT
was licensed only for terminal disease, but this
finding caused the trial to be halted and the product
to be approved for this use. But the decision was
based on a transitory data "blip", which
had caused the board to act prematurely. A longer
study, published four years later, found no
preventative effect.
Stopping
trials in this way before their scheduled completion
is now standard in Aids product development. "If
efficacy is observed at the time of a scheduled
interim efficacy analysis," Nowinski explains,
"the monitoring board will recommend termination
of the trial."
But
could bodies such as the Food and Drug Administration
and the European Medicines Evaluation Agency license
a vaccine that doesn't work on the basis of an
AZT-style blip? Evidence suggests that agencies under
political pressure take just such paradoxical steps.
The National Institutes of Health, for instance,
vetoed the VaxGen experiment as a waste of money and
volunteers. But after being accused of "a human
rights violation" by Dr Jonathan Mann, 51,
former WHO Aids chief (and who died with his wife,
Clements-Mann, also 51, in the Swissair crash), the
institutes not only reversed themselves, but granted
Francis $4.6m.
Sometimes
the clamour may be marshalled by persons who may not
be as detached as they seem. The Journal of Aids
Research and Human Retroviruses, for instance, has an
editorial board that's a Who's Who of Aids. But
Francis paid the publisher $10,000 for the
"special issue", which Berman edited as a
"guest". As for some of the contributors,
Francis helped to set up Berkley's international
vaccine initiative and advised Bill Gates's charity
foundation to give it $25m. He has done a deal to
supply proteins to the rival manufacturer which
employed Clements-Mann. And he has offered the CDC's
Heyward the post of VaxGen vice-president, starting
next January.
Pressure
also comes from powerful bodies which have long-held
institutional agendas. The CDC, which mostly collates
disease data, first became a significant health
service body due to polio vaccine, launched in April
1955. The WHO's singular success was smallpox
eradication, accomplished in October 1977. Mass
immunisation is what they know best. It's simply what
they do. "Don Francis reminds them of when they
were young," Dr John Moore, of New York's Aaron
Diamond Aids Research Center, told me.
What
worries critics such as Moore is that political and
institutional pressures may lead to millions of
people being injected with AidsVax before the
benefits and risks are clear. The WHO estimates that
annual demand for the first vaccine will be 650m
doses and UNICEF leaders are thinking about adding it
to programmes for 100m children.
Francis
anticipates that the CDC, which has already granted
him $8m, is to finance a US immunisation campaign
and, in Europe, national health services will pick up
the tab. "In addition, the International Aids
Vaccine Initiative has started a campaign to fund the
development and purchase of an HIV vaccine for the
developing world," VaxGen documents say.
"In meetings with us, the World Bank has
indicated that it's exploring the potential for
low-interest loans to support the purchase."
One
of the snags which may be overlooked in this rush is
the effect on recipients' behaviour. Common sense
says that somebody who thinks that they may be
protected is more likely to take chances with risky
activities than a person who knows that they aren't.
One study of this effect in 1997 found that unsafe
sexual behaviours doubled among gay men in
preliminary vaccine tests. If this was repeated
globally, the impact of an even vaguely effective
AidsVax may be that the Aids epidemic gets worse.
*****
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