There is growing global momentum behind the call to begin to end the AIDS epidemic using the scientifically-proven options available today. These include voluntary medical male circumcision, antiretroviral therapy (ART) -- which dramatically reduces risk of HIV transmission between stable sexual partners -- and prevention of pediatric infection during pregnancy, delivery and breastfeeding. If taken to scale with resources and urgency, these core components of combination prevention, along with other key prevention interventions, can save lives, prevent new infections and lower the price tag for the global AIDS response over the long term.
More new strategies could be coming soon. Just last week, an advisory committee to the U.S. Food and Drug Administration recommended approval of the antiretroviral TDF/FTC (brand-name Truvada) for pre-exposure prophylaxis (PrEP) in HIV-negative adults. A final decision from the FDA is expected in June -- and approval would provide another powerful option for HIV prevention.
If the world acts with strategy and speed to implement the proven and emerging options, the epidemic should be on a measurable downward trajectory over the next five to ten years.
Why, then, do we still need an AIDS vaccine?
Because we want to end the epidemic.
If the potential of combination prevention is realized over the next ten years, there will be vast reductions in the numbers of new HIV infections and AIDS deaths. If combination prevention targets do not get met in the next ten years, this will be a global tragedy.
In either scenario, an AIDS vaccine is an essential tool.
This is because in both of these scenarios there will still be new infections. Ideally, an AIDS vaccine will be a prevention tool that helps bring the epidemic closer to a more definitive end. And if the world fails to act on the promise of new tools -- as it has with other imperatives, such as elimination of pediatric infection -- then a preventive vaccine would be even more urgently needed.
History tells us that vaccines are among the most powerful public health tools available and that personal preferences matter at an individual and programmatic level. The world needs as many potent HIV prevention options as possible. Whenever it is developed, an effective preventive AIDS vaccine will be a critical choice for many.
In the best-case scenario, a vaccine is cheap, easy to administer and offers lifelong protection after a single immunization. Someday an AIDS vaccine might fit that description. However, today the regimens being tested are more complex -- such as the six-shot regimen evaluated in an AIDS vaccine trial in Thailand, called RV144, the first trial to show protection in humans. And although the initial protection was strong, this response weakened over time and was quite modest; by the end of the trial, people who received the vaccine had an approximately 31 percent reduction in HIV transmission compared to those who received the placebo.
Today scientists believe that the RV144 strategy can be improved upon to provide better protection at a global level. There are a series of follow-on trials planned in Thailand, where RV144 took place, and South Africa. Ideally, these trials will coincide with expanded implementation of combination prevention tailored to the epidemics in these contexts.
In order for these and future trials to be successful, AIDS vaccine advocacy needs to articulate the role of a vaccine in the context of an expanded array of powerful prevention options offered in programs around the world.
For years, AIDS vaccine advocates have reminded the world that vaccines are the most powerful public health tools on the planet. This is still true. At the same time, the current, hopeful context for beginning to end AIDS using available tools places an imperative on AIDS vaccine advocates. We must shape an agenda that is contextual and bridge-building. The best advocacy will move away from the rhetoric of "the best hope" or "the only tool" for ending the epidemic. It will situate an AIDS vaccine within the scale-up of combination prevention. "Yes," vaccine advocates need to say, "Yes, an AIDS vaccine could be a uniquely powerful tool. And the best possible world in which to deploy such a vaccine is one in which the epidemic is already slowing down."
It's not just messages. Actions matter, too.
There is promising work that points us in the right direction. International partners are mapping out the steps needed to prepare for RV144 follow-on trials, and researchers focused on understanding how the antibodies that successfully fight HIV actually work have also set out milestones for what promises to be a critical decade of discovery. Going forward, these three priorities strike us as critical.
• Continue and broaden AIDS vaccine advocacy. Everyone who is an HIV prevention advocate can, and should, be a vaccine advocate. But this means honest discussions about how AIDS vaccines fit into combination prevention; the necessity for future trials, including large-scale efficacy trials; and the way that these trials will integrate new prevention options into the design and standard of prevention.
• Sustained funding for the science. In 2011, funding for basic science was significantly lower than the recent peak in 2008. Yet the field of neutralizing antibody research has steadily offered up key breakthroughs, and there is every reason to think this will continue into the future. The funding has to remain steady to keep the science on track and build on these recent discoveries.
• Set and communicate milestones for measuring progress -- and adjust accordingly. As the timeline demonstrates, there are timeframes for progress in RV144 follow-on trials, antibody research and development of other novel candidates. We must monitor these milestones, add new ones, maintain a robust pipeline and demonstrate nimble course correction. Progress to-date has depended on field-wide collaboration facilitated by inter-institution data -- and materials transfer agreements. It's critical to attend to these enabling factors at every stage.
Tomorrow, on HIV Vaccine Awareness Day 2012, AIDS vaccine advocates can show the world what it means to be "Ending AIDS advocates" -- and how a combination prevention agenda that includes scaled-up delivery of today's tools and a sustained commitment to developing new ones, especially an AIDS vaccine, is the best hope for the future. A single intervention can neither save the day on its own, nor be neglected as we pursue this essential goal of ending the epidemic.
For a suite of new resources that AVAC has developed to help advocates add depth and detail to these much-needed conversations, including a new series - AIDS Vaccines for Busy Advocates - that provides one-page summaries on three key issues, visit www.avac.org/vaccines.
Follow Mitchell Warren on Twitter: www.twitter.com/@hivpxresearch