Experimental HIV Vaccine Fails, Government Halts Study

An experimental HIV vaccine fails, adding to the latest roster of bad news in the hunt for an AIDS vaccine. Since the experimental shots aren’t preventing HIV infection when it was tested, the U.S. government is halted a large U.S. study for finding for an HIV vaccine Thursday, reported the Associated Press.

The shots also did not reduce the amount of AIDS virus in the blood when people who’d been vaccinated later became infected, according to the National Institutes of Health.

“It’s disappointing,” said the head of NIH’s National Institute of Allergy and Infectious Disease, Dr. Anthony Fauci. He mentioned, however, "there was important information gained from this," inferring that the study will help determine what to try next.

The recently halted study enrolled 2,504 volunteers, mostly gay men, in 19 cities in 2009. Half of the volunteers received dummy shots, and half received two-part experimental vaccine developed by the institute. All individuals who participated were given free condoms and extensive counseling on the risk of HIV.

The strategy applied in the study is known as “prime boost.” A DNA-based vaccine made with genetically engineered HIV material is given to prime the immune system in order to attack the AIDS virus. A different vaccine is then used, one encased in the same material inside a shell made of disabled cold virus. The different vaccine acts as a booster shot to strengthen the response. Neither of the vaccine could cause HIV.

The idea for the experiment was to train immune cells to know T cells to spot and attack the very earliest HIV-infected cells in the body. The hope for the vaccine is that it would prevent HIV infection or help those infected fight it.

A safety review this week revealed that slightly more study participants who had received the vaccine, later became infected with HIV. It is unknown why. The difference, however, wasn’t statistically significant, possibly signifying that it’s due to chance. Overall, 41 HIV infections were known in the vaccinated group and 30 amongst the ones who received a placebo. When researchers examined only participants diagnosed after being in the study for at least 28 weeks – long enough for the shots to have done their job – there were 27 HIV infections among those vaccinated and 21 among the placebo recipients.

According to the NIH Thursday, it is stopping vaccinations in the study, known as HVTN 505, but researchers will continue to study the health of volunteers.

Josh Robbins, 30, of Nashville, Tenn., were amongst the participants who became infected with the virus. He was, however, glad he participated in the study because it’s monitoring meant he was diagnosed and treated much more sooner than most people.