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PUBLIC RELEASE DATE:
3-Apr-2014

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Contact: NIAID Office of Communications
niaidnews@niaid.nih.gov
301-402-1663
NIH/National Institute of Allergy and Infectious Diseases

HIV vaccine research must consider various immune responses

WHAT:

Last year, the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, held a scientific meeting to examine why certain investigational HIV vaccines may have increased susceptibility to HIV infection. In a new perspectives article appearing in the journal Science, HIV research leaders from NIAID (Anthony S. Fauci, M.D., and Carl W. Dieffenbach, Ph.D.) and its grantees at Emory University (Eric Hunter, Ph.D.) and the University of California, San Francisco (Susan Buchbinder, M.D.), summarize the findings and considerations for future HIV vaccine research.

Between 2005 and 2013, investigational HIV vaccines based on recombinant adenovirus type 5 (rAd5), a weakened type of cold virus designed to deliver genetic material, were tested in three clinical trials. Two of those studies, known as Step and Phambili, involved the same experimental vaccine. Both studies showed no efficacy against acquisition of HIV infection; however, they suggested an increased risk of HIV acquisition among vaccinated male study participants. Based on subsequent analyses, the authors hypothesize that the rAd5-based vaccines tested may have heightened susceptibility to HIV infection by activating for sustained periods CD4+ T-cells, the key target for HIV, while producing ineffective or limited protective effects against HIV.

Given the lack of efficacy demonstrated by rAd-5 based HIV candidates and the potential increased risk for HIV acquisition, further development of HIV vaccines using rAd-5 vectors are inappropriate, the authors write. Researchers who want to pursue HIV vaccines using different adenoviruses or other vaccine delivery systems should perform a risk-benefit analysis that weighs the balance between the potential anti-HIV vaccine responses and protective benefit of the vaccine against the vaccine-induced risk of increased HIV acquisition due to heightened CD4+ T-cell activation. Moving forward, the HIV vaccine research field would benefit by clarifying the role vaccine vectors play in overall HIV vaccine effectiveness, identifying biomarkers in nonhuman primates that indicate increased risk for HIV acquisition, and developing a better understanding of mucosal immune system responses to HIV vaccination, according to the authors.

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ARTICLE:

AS Fauci et al. Immune Activation with HIV Vaccines. Science. DOI: 10.1126/science.1250672.

WHO:

NIAID Director Anthony S. Fauci, M.D., and Carl W. Dieffenbach, Ph.D., director of NIAID's Division of AIDS, are available for comment.

CONTACT:

To schedule interviews, please contact the NIAID Office of Communications, (301) 402-1663, niaidnews@niaid.nih.gov.

NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov/.

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