Public health officials in Thailand announced on Sept. 24 that an HIV vaccine has shown 30 percent effectiveness in preventing disease in the general Thai public. Preliminary studies that led to the development of the vaccine were performed at UR in the late 1990s.
The vaccine is a combination of two vaccines one that is intended to kill HIV cells and the other that helps the body to produce antibodies to fight off the disease. It is the first of its kind to show conclusive evidence that a vaccine can work in humans.
Primary investigator of the Rochester HIV Vaccine Trials Unit and Professor of Medicine Michael Keefer helped conduct the preliminary research that eventually led to last week’s findings.
‘It’s exciting mainly because it shows that it is possible to prevent HIV in humans,” Keefer said. ‘For a person like me who lives and breathes this research every day, this is huge. For the average person looking to get a vaccine from their doctor, that is probably years off.”
This is the first vaccine to show even limited potential in preventing HIV in humans. The seven-year study tracked 16,000 HIV-negative men and women ages 18 to 30 in Thailand who received the vaccine.
The study was double-blind, meaning that neither participants nor investigators knew which participants received which form of the vaccine. Of the participants who received the placebo, 74 became infected with HIV compared to 51 participants who received the vaccine.
The vaccine had only a 30 percent success rate, which means it can’t be licensed for use in any country. Most vaccines need to have higher than 95 percent effectiveness to be licensed for use. According to reporting by BBC World, major efforts will be directed toward data analysis of study results to improve the effectiveness of future vaccines.
Keefer has been studying HIV since 1988 when UR was one of only two sites worldwide studying the epidemic. Typically, the HIV Vaccine Trials Unit carries out phase I trials in people. The studies recruit a small number of low-risk volunteers for preliminary studies. Due to the presence of the vaccine unit, Rochester is one of the top cities in the world for participation in the search for an HIV vaccine.
‘Now more than ever we need people to support our research efforts,” Keefer said.
UR is currently recruiting volunteers for local studies. UR is also assisting in a nationwide Phase II trial in the United States and Canada. The trial will test 3,000 patients on the effectiveness of a different type of HIV vaccine made from an inactivated cold virus.
Keefer stressed that a major concern in vaccine development is safety.
He explained two primary difficulties in developing an HIV vaccine. First, a vaccine works by activating the immune system against disease. However, HIV targets activated cells in the immune system. Therefore, some earlier HIV vaccine attempts have actually increased the risk of HIV infection instead of decreasing it.
Secondly, the virus is capable of mutating to adapt to the genetic diversities of a given population. For this reason, the Thai strain of the virus looks different from the virus in other parts of the world. In developing a vaccine, scientists are looking to target critical elements of the virus common to all strains.
According to the World Health Organization Web site, HIV has infected more than 60 million people worldwide and continues to spread at a rate of 14,000 new infections each day.
‘Despite preventative measures, a new person contracts HIV once every eight seconds,” Keefer said.
Sahay is a member of the class of 2010.