Researcher: HIV vaccine needed to end epidemic
“The DNA prime is sort of like pouring water down a pump, where you pour a little bit of the pump down the well to prime it. It’s the little bit that allows your body to recognize the virus and fight it,” Robinson said.
Robinson’s vaccine started Phase II human trials in January 2009 and involves 225 participants at sites in the United States, including Emory University’s Hope Clinic, and South America.
The next stage, scheduled to start in 2014 and last three years, would examine high risk populations, which would include gay men.
Robinson’s team is also moving forward with a separate trial to test if the vaccine can control the infection in those who have already been exposed.
“For people who are positive already, we have a therapeutic application that we are working on, and we have a very small open label trial going on,” Robinson said. “In that trial we have several people who have recently undergone seroconversion. They go on drugs within 18 months of their infections, and they have to have the virus well controlled and then we give them the vaccine.”
‘Crafty virus’ still kills millions
HIV research has seen unparalleled expan- sion in the years since Merck made the results of the Thailand trial public.
“What we expect to see now, between now and the end of the decade, [is] a series of human efficacy trials that are building on the [Thailand] stories, that are building on the better vectors that have advanced into clinical trials,” Koff said.
Researchers routinely build on each other’s results and failures. Robinson’s vaccine is different from other previous vaccines because it includes a macrophage colony stimulating factor, which helps activate the immune system.
“They’re the ones that will see the virus-like particles and take that to the B-Cells and the Tcells to initiate the immune response,” Robinson said.
That vaccine uses techniques that have not been tested before, and more new studies are published nearly monthly.
In October, the Centre for the AIDS Programme of Research in South Africa reported finding two new vulnerabilities in the HIV protein coat. In November a Canadian research team announced successfully clearing Phase I human testing with a virus that uses dead HIV virus.
“There have been a series of vectors of vaccine candidates, some are weakened forms of viruses, some of them are different forms of boosts, some unique collections of antibodies… there are a number of studies that are about to go into trials that — just based upon the results in the primate studies — look to have a better chance at being more effective then the studies that have come before them,” Koff said.
While there are more studies using newly discovered techniques in the hopes of finding an effective cure, researchers are leery of setting timelines, or making overly optimistic predictions.
Even if Robinson’s vaccine proves to be highly effective it would be years before it is available to the public.
“For the preventive vaccine? I really think we’re going to have it, but I think it’s going to take at least five years, and then it’s going to be years before we can a make a product that we can manufacture that your doctor can give you,” Robinson said.
Koff is often asked if HIV could ever be fully eradicated like small pox and said he doesn’t know the answer.
“I don’t know if we know enough to fully answer that,” he said. “The reality is that we need a vaccine first. We have a lot of other tools in the tool box about HIV prevention, but without a vaccine it’s unlikely that we’re really going to be able to end the epidemic.
“I want to emphasize that, because every day you hear stories about … education, condom use, circumcision,” Koff added. “But even with all of those we still have over 7,000 HIV infections every day, and several million deaths from AIDS every year. The virus is crafty enough that it continues to find ways above and beyond our current prevention methods.”
Dr. Harriet Robinson is researching an HIV vaccine that she hopes could not only keep people from being infected, but reduce the viral load in people who are already HIV positive. (Photo courtesy GeoVax)