There's good news about AIDS vaccine
research. The World Health Organization
and UNAIDS say the largest ever HIV vaccine trial has yielded "very
encouraging" results. The agencies say,
"It's the "first demonstration that a vaccine can prevent HIV infection in the
announcement was made Thursday in Thailand, where the clinical trial, involving
over 16,000 adults, was conducted.
Warren, head of AVAC, the AIDS Vaccine Advocacy Coalition in New York, calls
the results a "historic milestone."
25 years now the world has looked for an AIDS vaccine and we have had clues
that an AIDS vaccine was possible…. But
it's only with the trial results announced today that we now have our very
first evidence in human trials that an AIDS vaccine is possible to actually
reduce the risk of HIV infection," he says.
Good news follows bad
years ago, what was thought to be a promising vaccine candidate from Merck failed
to protect against infection in clinical trials. The findings were a considered a major blow
to HIV vaccine research and many questioned research models. So what happened?
happened. And that is what I think this
result today tells us more than anything.
Science happens in a remarkable, unpredictable way," he says.
says the Merck trial was not a total failure.
trial succeeded in answering a question.
Unfortunately, the answer was that that particular candidate…didn't
adds, "What's amazing is that the trial result announced today has been in the
clinical trials for six years now. And
it was ongoing throughout that entire life of the Merck vaccine trial. And people pretty much dismissed this vaccine
Encouraging, yes, but…
says the Thailand trial involved a two-vaccine combination had "a modest
effect." So it's not ready to roll out
for general use.
he says, in that the "group that got vaccine had about a 30 percent reduced
chance of getting infected than those people who got the placebo – so about 30
percent fewer infections in the vaccine group."
calls the results a building block on which to build a better vaccine.
how high an efficacy rate is needed before a vaccine is ready to be rolled
process of determining how good is good enough is much more than a single
number from this trial. It really gets
decided by regulatory authorities in various countries, by communities in those
countries. And there isn't a straight
answer to what is the magic number to say this is good enough to roll out," he
Other factors come into play
a higher efficacy rate, researchers still need to know how often a person may
need to get the vaccine, whether it could be manufactured on a large scale and
at what cost.
this same vaccine work in another part of the world where the HIV strain is
different? We don't know…. This is not the beginning of the end of the
epidemic, this is the end of the beginning, a new chapter, really, in our
search," he says.
International AIDS Vaccine Initiative (IAVI) joins AVAC in praising the vaccine
trial results. IAVI President Seth
Berkley (MD) says, "The outcome is very exciting news and a significant
scientific achievement…. Now we've got a
vaccine candidate that appears to show a protective effect in humans, albeit
says the Thailand trial proves the importance of human trials.
can only learn so much from animal models.
We could not have learned what this study is going to teach us any way
other than through clinical research, and we expect to learn a great deal," he
But IAVI, AVAC, WHO and UNAIDS say
despite the promising results, access to care and treatment of HIV/AIDS remain