About a year ago, there was some discouraging news about AIDS vaccine research. A promising vaccine candidate failed when it apparently made test subjects actually more susceptible to HIV infection.

Many considered the news a major setback in research. But now IAVI, the International AIDS Vaccine Initiative, and the Scripps Research Institute have announced the creation of a new research center. Its goal is to find an AIDS vaccine by taking a different approach.

Dr. Seth Berkley is president and CEO of IAVI. From New York, he spoke to VOA English to Africa Service reporter Joe De Capua about why the new center is being launched.

"The news a year ago was about a trial looking at a type of immunity called cellular immunity. Traditionally, the way we create vaccines against diseases is by making vaccines that produce neutralizing antibodies against the particular virus. And that is what we'd like to do with HIV. We haven't known how to do that. So people moved into the cellular area trying to find other ways to get immunity that might be helpful," he says.

But Berkley says there were concerns as far back as five years ago about whether cellular immunity was the best approach. "About five years ago, we started a neutralizing antibody consortium, a group of laboratories?trying to solve this perplexing problem of neutralizing anti-bodies, which we know is solvable. And this latest announcement is one to expand that effort even further," he says.

IAVI's president explains the two vaccine approach. "The idea is that we would like to have both neutralizing antibodies and cellular immunity. The neutralizing antibodies is to try to prevent infections. Cellular immunity would be if some virus got through it would mop up and kill cells that were infected. So, in an ideal world, you'd like to have both. But if you could only have one of the two, neutralizing antibodies would be the one of choice. And so?years ago, we tried to understand the science better and move forward in trying to solve that problem," he says.

Berkley says it's known that neutralizing antibodies exist. "There now have been four or five examples of antibodies isolated from humans that neutralize most of the (HIV) strains in the world. And so the challenge then is how do you make a vaccine that produces antibodies like those," he says. In fact, some people's immune systems are actually able to keep HIV in check without the help of antiretroviral drugs.

The failure of an AIDS vaccine candidate last year is not a total loss. Berkley says it has triggered a lot of new research. As for the often-asked question ? when will there be an AIDS vaccine? ? Berkley says, "It's different now than it was a few years ago because we had candidates that were moving into efficacy trial and if those had worked you'd know exactly what the pathway was in timing. At this point?we're moving a little bit more upstream. So, it's very difficult to predict an actual time point. But what I'd like to say is that in essence this is a Renaissance period for AIDS vaccines because we now have a lot more science. There's a lot more work going on. And so, I trust the power of science and I personally believe that we will have breakthroughs?in the next few years, given the amount of effort and the critical mass of people that are working on these problems. And so I am optimistic that we will get there, but I can't tell you exactly when."