On Wednesday in Washington, the government stopped a large HIV vaccine study by the US because the experimental injections are not doing what they are meant to do: prevent infection with the virus.
Not only did the shots not stop infection with HIV, but they did not reduce the level of the virus that was in the blood when those who had been vaccinated became infected later. The head of the NIH National Institute of Allergy and Infectious Diseases said that the shutdown was disappointing and that there was essential information that the study had found.
In the study, over 2,500 volunteers across 19 US cities participated from 2009. Most of the participants were gay men. All of the participants were given condoms for free and received counseling regarding the risks for HIV. Half of the volunteers were given placebo injections, and the other half were given a two part vaccine that was still in the experimental stages. The injection was developed by the NIH.
The way the vaccine was created is often called “prime-boost.” It involves using a DNA based vaccine and combining it with HIV material that has been genetically engineered, and then injecting it into the body to help encourage the immune system to fight the AIDS virus. Once that step has been completed, an additional vaccine that is made up of the same materials as the first vaccine, but is encased in a deactivated cold virus is given as a way to boost the response that the first injection allows to begin. Neither of these vaccines had the potential to cause HIV.
This week, however, a review of the safety of this study found that a slightly higher number of participants who had been given the vaccine developed an HIV infection. Researchers are not certain as to why this happened, but they say that the study wasn’t significant to the study, and some feel that researchers are suggesting that the higher numbers may be simply by chance.
In all, the vaccinated group experienced 41 HIV infections, and of the volunteers who received a placebo, 30 had contracted HIV. When researchers examined only the volunteers that were injected with the vaccination after taking part in the study for a minimum of 28 weeks (which was long enough for the injections to have worked), 27 had developed HIV infections. Of the volunteers who received placebo injections, 21 had developed infections.
In theory, training the immune cells called T-cells to identify and attack extremely early HIV cells in the body, should work. Researchers were hoping to encourage just this reaction with the vaccination. Scientists are still optimistic that their findings are going to be helpful in future research.
For now, however, the study has been halted as it is too dangerous. Health care professionals agree that a way to fight AIDS is essential, but the studies were simply too dangerous for participants.