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AIDS Vaccine Trial Failures Trigger Debate and Controversy


There’s news today of a major setback in the search for an AIDS vaccine. The Washington Post newspaper reports that two trials of the most promising vaccine candidate not only did not protect people from the aids virus, but may have actually put them at risk of infection.

Both field trials have been halted, including one in South Africa known as the Phambili trial. The Post reports that the US National Institutes of Health, which funded both trials, will host a meeting next week to discuss vaccine research and what went wrong.

For an analysis of the failed trials and the overall vaccine research, VOA English to Africa Service reporter Joe De Capua spoke with Mitchell Warren, executive director of the AIDS Vaccine Advocacy Coalition in New York.

He says, “I have two reactions. One is frustrated in that there is no news in that story that’s new. This information’s been out for months now. But secondly and I think more importantly, my feeling is one of also frustration about both how challenging the search for a vaccine is and how that frustration plays out in really difficult ways. And certainly the results of the recent vaccine trials are a tremendous setback to the field, but I think people kind of go so much further in exaggerating it. And I think it shows really a misunderstanding of the product development process. Developing an AIDS vaccine or developing any biomedical intervention is an incredible challenging exercise. And the product development process is more often filled with setbacks than advances.”

Warren adds, “Setbacks are things we always want to avoid certainly. Sometimes that is how science moves.”

The Merck pharmaceutical company produced the vaccine candidate. One trial, known as STEP, took place in the United States and had about 3,000 volunteers, while the Phambili trial in South Africa was much smaller, with about 800. The vaccine used the Adno-5 cold virus that contained some DNA from the AIDS virus, HIV.

“It was used to teach people’s immune system about HIV…. The vaccine could not, does not cause HIV (infection)…. And these trials are called test of concept trials,” he says. Researchers stopped immunizing people in September “because an independent group that looks at the data…said it was futile to go forward…. It wasn’t going to reach its conclusion with a definitive answer. And that’s why it was stopped,” he says.

In November, it was found there was a trend toward more people in the vaccine arm getting HIV than in the placebo. Warren says it’s known participants were involved in risky sexually behavior, despite counseling and the availability of condoms. But researchers must determine why they appear to be more susceptible to infection after receiving the vaccine. “We don’t know (why) definitively,” says Warren.

He praises the monitoring board of the trials for acting very quickly to stop them. “Their highest priority was to protect the safety of participants,” he says.

For a further look at what the vaccine trial failure means, reporter De Capua spoke with Professor Alan Whiteside of the University of KwaZulu-Natal in South Africa. Professor Whiteside is co-author of the book: AIDS in the 21st Century.

“I think it’s extremely depressing that there isn’t a vaccine yet; and I think one also has to be aware that there isn’t one available in the short term. It is undoubtedly a setback for AIDS prevention. But at the same time, it is telling us we need to be looking at some of the underlying causes of infection. And that there aren’t quick, biomedical fixes for this disease,” he says.

However, solutions need to be tailored to different regions. “First of all, what we have to recognize is that the epidemic is greatly differentiated across the world. In the part of the world that I live in, southern Africa, we have what we call hyper-epidemics, where up to 20 percent of the population is infected. In much of the rest of the world the epidemic isn’t as serious, although its impact may be considerable. So, the question is what’s driving the epidemic…. And the answer would seem to lie in inequality, particularly gender inequality, which leads to people putting themselves at risk,” he says.

Whiteside says empowering women and behavior change are key. “It’s about women not having the power to say with whom they will have sex, when they will have sex and how they will have sex in the sense of being protected. It’s about men believing there are certain expectations of them in relationships as well. So, it is an enormously complicated issue. And I think for us in southern Africa, the one thing, which we also look at with concern, is concurrency of partners, where people have partners fairly close together,” he says.

Whiteside does see the news of the latest trials changing AIDS policy much. “Perhaps what we will start doing is looking for the social vaccine that we need. It’s ironic because there are certain things that one could do, which would stop the epidemics in their tracks. For example, one idea that I’ve been toying with is if you could get an entire nation to either use condoms for either every sexual act or to abstain from sex. Let’s just say everybody does it (abstain) for eight weeks. Then that would actually have a huge impact on the transmission dynamics of this epidemic. It’s simple, effective. Could it happen? I don’t know,” he says.

The University of KwaZulu-Natal professor warns he’s beginning to see a gap between resources and needs; and is concerned whether too much hope is being pinned on science to end the HIV/AIDS and not enough on the social aspects.

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