New Partnerships Are Needed in Search for AIDS Vaccine, Experts Say

Confronted by new spending constraints, new collaborations involving government, industry and academia are needed to make the best use of available resources in the search for an AIDS vaccine, experts said this week at the AAAS Annual Meeting.

After years of substantial increases, the budget at the National Institutes of Health (NIH) is expected to increase by less than 2 percent in the 2006 budget proposed this month by the White House. Funding for HIV/AIDS vaccine research and development may fare somewhat better, said Anthony S. Fauci M.D., director of the National Institute of Allergy and Infectious Diseases.

Speaking to reporters at a AAAS news briefing Monday in Washington, D.C., the AIDS experts said they face continuing challenges in the production of clinical grade vaccines, expansion of clinical trials in wealthy and developing countries and strengthening public-private collaborations. Collaboration between the private and public sectors to meet the scientific challenges of developing a safe and effective AIDS vaccine is crucial to controlling the spread of the HIV virus globally, they said.

"The movement towards a viable AIDS vaccine needs to be a truly global effort. This isn't a sprint, but a marathon," said Seth Berkley, president and founder of the International AIDS Vaccine Initiative.

"We are being appropriately told that we need to examine our entire research portfolio and also to look at cooperation and collaboration with industry in a way that can get the most bang for the buck," added Fauci, who is one of the world's leading authorities on HIV/AIDS.

According to Fauci, agencies and private companies are working together to avoid unnecessary overlap and duplicative efforts to ensure the most efficient and cost effective research and development of the vaccine.

Observations from human and animal studies suggest that a useful HIV vaccine is possible. Numerous vaccine strategies are in various stages of preclinical development designed to optimize cell-mediated immunity—which would not prevent HIV infection, but would deter the progression of the disease.

Cellular immunity, or cell-mediated immunity, is an immune response (chiefly against viral or fungal invasions or transplanted tissue) that involves T lymphocyte cells eliminating HIV-infected cells. An individual would have to be contract the HIV virus first in order for the vaccine to destroy the infected cells.

Berkley believes that the race to develop an effective vaccine has reached a fork in the road. If researchers are successful with the path of cell-mediated immunity, then there are currently several vaccine candidates already in development. However, if an effective treatment requires the induction of neutralizing antibodies, then creating a successful vaccine will be a longer process.

"Cell-mediated immunity is important to prevent the progression of a virus, but antibodies are tailor-made to block the virus from ever infecting the cell," said Fauci. "I doubt very seriously whether we'll have a successful vaccine candidate that will prevent infection until we're able to induce neutralizing antibodies along with cellular immune responses."

Berkley agreed. "The vaccine will probably require neutralizing antibodies to protect against infection," he said. "Ideally, we want a vaccine that incorporates both."

The research and development of an AIDS vaccine remains a top priority for the NIH. Fauci said that last year $600-700 million was invested on AIDS vaccine research worldwide—of which the vast majority of the resources were paid by the United States ($520 million from the NIH and $62 million from the U.S. Department of Defense).

According to the Joint United Nations Programme on AIDS (UNAIDS) approximately 39 million people are living with HIV, and an estimated 4.9 million people were newly infected with HIV in 2004 alone.

The ideal HIV vaccine would be inexpensive, easy to store and administer and would elicit strong, appropriate immune responses with long-lasting protection against HIV infection by exposure to infected blood and by sexual contact. The vaccine would also protect against exposure to many different strains of HIV.

— Monica Amarelo

23 February 2005