An experimental HIV vaccine that focuses on three of the most prevalent strains of the virus worldwide entered clinical trials this week, the National Institutes of Health reports. The vaccine, developed at the Dale and Betty Bumpers Vaccine Research Center, part of the National Institute of Allergy and Infectious Diseases, incorporates genetic material from HIV's A, B, and C subtypes, which together cause about 90% of all HIV infections around the world.
"This is the first multigene, multiclade HIV vaccine to enter human trials," said NIAID director Anthony Fauci. "It marks an important milestone in our search for a single vaccine that targets U.S. subtypes of HIV as well as clades causing the global epidemic."
The vaccine incorporates parts of four key HIV genes--gag, pol, nef, and env--that are designed to prime the body's immune system to recognize and attack whole copies of the virus in the body. The gag, pol, and nef genes are derived from HIV clade B, the most common form of the virus in the United States and Europe. The vaccine also includes modified env genes from all three HIV clades. Because the vaccine uses only small pieces of HIV's genetic material, there is no threat of infection with the virus for those who are inoculated.
The first phase of the clinical trials, which is being conducted at the NIH in Bethesda, Md., will include 50 HIV-negative volunteers and is aimed at gauging only the safety of the compound. The safety study is expected to last one year. Future tests are planned for the United States, South Africa, and Haiti to determine the vaccine's efficacy in producing an immune system response to the virus.