The elusive dream of an AIDS vaccine is one step closer to reality. Last
week an historic announcement was made in Thailand: the world's largest HIV
prevention trial showed that an AIDS vaccine is possible.
And it also seemed to prove that science at its most exhilarating is
unpredictable and downright surprising. Before it even enrolled the first of
its 16,400 volunteers, the Thai prime-boost trial was labeled a guaranteed
failure by critics, many of whom questioned its design and whether it should
go forward at all.
Five years later, thanks to the dedication of the volunteers, trial staff
and sponsors, we have the exciting news that the vaccine regimen is the
first in history to show an impact on risk of HIV infection. The protective
effect -- roughly 30 percent -- is modest, to be sure. In the weeks and months to
come there will be difficult questions about what the next steps should be
in terms of research on this strategy and on the entire AIDS vaccine field
as a whole.
But before embarking on this necessary process of questions and, no doubt,
debate, the world should take a moment to celebrate an historic finding that
many stalwart AIDS vaccine advocates did not believe would come in their
To put it in context, two years ago many people were asking if the dream of
an AIDS vaccine was over. Were we wasting millions of dollars on a fruitless
search for a vaccine that seemed to grow more and more elusive?
These questions were prompted by news of the failure of what was then seen
as the most promising AIDS vaccine candidate to enter clinical trials. The
failure of this candidate, MRK-Ad5, demoralized researchers and advocates.
In the aftermath, critics within and outside the field questioned the wisdom
of conducting any more AIDS vaccine trials in humans and even asked whether
an AIDS vaccine was a realistic goal for the HIV prevention field.
In these discussions, the Thai prime-boost trial was frequently an
afterthought. It was certainly not expected to be the trial that buoyed
hopes and brought to an end the first chapter of AIDS vaccine research
twenty years before a proof of concept that a vaccine is possible.
As we celebrate, we must also remember that there are many, many steps from
a proof of concept (as demonstrated in this trial) to a licensed vaccine
that can be introduced (which is certainly not warranted based on this one
In the near- and mid-term it will be critical that these results are
explained to the full range of relevant stakeholders in a balanced and
thoughtful way. This is the first step, not the end of the road. As the
trial team has made clear, the broader scientific community will need to
provide expert input on how these results impact on other vaccine research
and on additional research that should be undertaken with this or similar
regimens to learn more about it specifically.
The bottom line is that this is both cause for celebration and a complicated
result. It doesn't mean that tomorrow the citizens of Thailand or any other
country can roll up their sleeves and stand in line to get an AIDS vaccine.
We're still a long way from that.
So how do we move from this modest effect in a clinical trial to a tangible
public health good?
Additional scientific research and studies are a large piece of a very
complex puzzle. But, we have several other herculean tasks ahead of us that
will require unprecedented cooperation among researchers, funders,
policymakers, advocates and communities.
We must begin to discuss in specific terms what the world might do with a
partially effective AIDS vaccine.
Such a vaccine would be enormously valuable as part of a combination
approach to HIV prevention. However, most people equate a vaccine with
complete protection from a disease, and it will be difficult to convey what
a partially effective vaccine would and would not do. Advocates, social
scientists and community members must begin to work now to develop ways to
explain how a partially effective AIDS vaccine will work along with other
prevention methods to help protect individuals from HIV infection.
Pharmaceutical and biotech companies and other partners must think now about
manufacturing capacity, both for the doses needed for any new trials of this
vaccine combination and for any eventual licensed vaccine, and legislators
and funders must determine how we will finance manufacturing and
distribution when we eventually do have a vaccine that can be licensed.
Regulatory officials in Thailand and other countries hardest hit by AIDS
must develop clear policies and pathways for licensing partially effective
vaccines and other new prevention strategies, and policymakers in those
countries must develop policies and guidelines for including partially
effective AIDS vaccines in their HIV prevention programs.
And we must all redouble our efforts to expand access to existing HIV
treatment and prevention programs around the world and to sustain investment
in research and development for AIDS vaccines and other biomedical
prevention options, including microbicides and pre-exposure prophylaxis
Throughout, advocates must work as aggressively as the researchers to ensure
that the perspectives of communities are represented in planning for
additional trials and for future access, and we must hold each other
accountable for proceeding quickly and transparently.
We still have a long way to go before we can end the AIDS epidemic, but this
week's news brought us closer to the finish line.