3 Questions: AIDS researchers on new vaccine results

On Thursday, an international research team reported that a new AIDS vaccine tested in more than 16,000 volunteers in Thailand protected a small but significant minority against infection. The new results mark the first time any vaccine has shown even partial success in clinical trials. In this interview, Arup Chakraborty, MIT professor of chemical engineering, chemistry and biological engineering, and Bruce Walker, physician and investigator at Massachusetts General Hospital, share their thoughts on the new study. Walker directs the Phillip T. and Susan M. Ragon Institute, a collaboration between MIT, Harvard and Massachusetts General Hospital launched earlier this year with a $100 million gift and the mission to develop an AIDS vaccine. Chakraborty is a team leader at the Institute.

Q: What is your reaction to the new study? How big a step forward is this in the search for an AIDS vaccine?

A: The data are clearly exciting because they are the first suggestion in humans that one might be able vaccinate people to lower the chance of getting infected with HIV. The effect was very modest, so it is clear that this vaccine is not the answer, but it gives us important clues to follow to get to a vaccine with a stronger effect. These results also could end up not being significant - we don't yet know if the groups were matched for other possible confounding variables that affect transmission like HSV-2 infection and circumcision, which could influence the results.

Q: What challenges remain in the effort to develop an AIDS vaccine?

A: At the current time it is unclear what this vaccine did to provide weak protection, so it is unclear what needs to be boosted to make it better. Of 16,000 people in the trial, there were 70 infections in those that got a placebo, and 51 in those that got a vaccine - not a huge benefit, but a signal nevertheless that the vaccine had some effect. The Ragon funding will allow us to move forward as quickly as possible to follow up on the clues from this trial.

Q: How does this advance affect the mission of the Ragon Institute, which was founded with the goal of developing an AIDS vaccine?

A: The data to us provide further support that an effective vaccine is possible. We have a long ways to go, but this is potentially a very important new clue to guide us.