Sexual Health news - HIV

Researchers find mechanism behind HIV vaccines efficacy


In 2009, a study on 16,000 Thai adults that was funded by the National Institutes of Health revealed that an HIV vaccine known as RV144 was partially effective in preventing the transmission of the notoriously hard-to-treat virus.

Subjects who received the vaccine were 31 percent less likely to become infected with HIV than their counterparts who were administered a placebo. This effect left scientists wondering how the vaccine worked, and they recently announced a finding that may provide an explanation.

Authors of the study, which was published in the New England Journal of Medicine, reported that the key is high levels of one specific antibody combined with low levels of another.

Apparently, having a large amount of an antibody that bonds to the outer coat of HIV known as the first and second variable regions, or V1V2, has a protective effect when the vaccine is introduced to the body. On the other hand, low levels of an antibody that bonds to the first constant region, or C1, of HIV seems to promote the vaccine's efficacy.

"This analysis has produced some intriguing hints about what types of human immune responses a preventive HIV vaccine may need to induce," said National Institute of Allergy and Infectious Diseases director Anthony Fauci, M.D. "With further exploration, this new knowledge may bring us a step closer to developing a broadly protective HIV vaccine."

Next, the study authors hope to incorporate their findings into studies on primates and the RV144 vaccine, as well as other inoculations. Additionally, the researchers want to find whether the discovery applies to all vaccines or only the RV144 that was used in the 2009 study.