A PIVOTAL MOMENT IN HIV PREVENTION

Last week's announcement about the failure of the leading AIDS
vaccine candidate developed by Merck & Co. is another in a series of
disappointing setbacks in HIV prevention. How we as a global
community choose to respond to this news, however, is the real test.

Historically, it has taken decades -- and more setbacks than advances
-- from the discovery of a virus or bacteria until an effective
vaccine is licensed. Typhoid was discovered in 1884, but there was no
vaccine until 1989. Malaria, discovered in 1893, still has no
vaccine. The measles vaccine took 42 years to develop.

In the 1930s, two experimental polio vaccines failed because they
were determined to be unsafe, and polio vaccines were almost
abandoned. At the time, we understood how to prevent infection by
sanitation and avoiding public swimming areas, just as we know how to
stop HIV infection today. We needed new tools then, and we need them now.

Today's question of how we deal with these setbacks will loom large
in any reckoning of our response to the most severe epidemic of our time.

There are more than 4 million new infections every year. In South
Africa, where three of this year's prevention trials have taken
place, there are communities where nearly one-third of women between
25 and 29 are infected with HIV. For every one individual who starts
on life-saving antiretroviral medications, there are six others who
are newly diagnosed.

These are mind-numbing, tragic figures. They remind us that there is
only one viable answer to the question -- "What do we do now?" --
that has been posed by many observers inside and outside of the HIV
prevention field in recent weeks.

We do more of everything.

There is a drastic shortfall in funds for implementing proven
prevention strategies, including male and female condoms, clean
needles, prevention of mother-to-child transmission and
risk-reduction counseling. In December 2006, we learned that male
circumcision showed strong protective benefits for HIV-negative men.
This strategy must also be made available in communities where it can
have an impact.

We must do more to bring comprehensive care, treatment and support to
people already living with HIV worldwide. Global targets have been
set and missed and are in danger of being missed again.

And while we do those things, we must continue to search for
additional prevention strategies, including vaccines, microbicides,
oral prevention or pre-exposure prophylaxis and herpes treatment.

To pit proven prevention and treatment against research is a false
and dangerous dichotomy. The range of tools that we have today is not
reaching every person at risk. And even if it did, it is not enough.
Women and men, adolescents, boys and girls and infants need more
choices when it comes to HIV prevention.

The best approach to prevention is one that provides the most
options. There will be no magic bullet, be it a condom or a clean
needle today or a vaccine tomorrow. There is only the ethical and
moral imperative to develop a multi-faceted response that is a match
for the multiple drivers of the epidemic.

In the wake of the failure of the Merck vaccine, the AIDS vaccine
field will need to make carefully considered decisions about whether
to move forward with planned trials of other vaccine candidates, but
the field will keep moving forward. It must, as the history of other
epidemic diseases tells us that an essential tool to stopping
epidemics is an effective vaccine.

As disappointing as recent failures are, donors and advocates,
scientists and physicians, volunteers and their families must all
guard against "failure fatigue." We must respond loudly and clearly
to suggestions that enough money has been spent; that it would be
easier and wiser to move on rather than to press on.

To do so would be to ignore the reality of the epidemic today, and to
overlook the lessons from history about the long, slow process of
vaccine discovery. We cannot afford to walk away from science, or
from the generations to come. Rather than giving up hope, we must
redouble our efforts in prevention research and stand firm in our
commitment to scientific inquiry. Millions of lives -- today and
tomorrow -- depend on it.

Glenda Gray is the co-director of the Perinatal HIV Research Unit in
South Africa. Mitchell Warren is the executive director of the AIDS
Vaccine Advocacy Coalition in New York.