October 21, 2009
As the AIDS vaccine conference continues in Paris this week, Reuters examines how recent trials are helping researchers better understand ways to develop a vaccine that offers people protection from HIV. Researchers involved in Merck's AIDS vaccine trial, which was halted in 2007 after it was feared the vaccine raised study participants' risk of infection, presented follow-up data from the trial during the conference on Tuesday.
Contrary to the first analysis of the data, additional analysis showed the AIDS vaccine likely did not increase patients' vulnerability to HIV, Susan Buchbinder, of the San Francisco Department of Public Health, explained to the conference. "The bigger picture issue is that we see some clues here and some clues there about ways where the vaccine may be providing some protection. Overall it didn't protect, but can we learn something about places where the vaccine may have provided even small amounts of protection so that we can build on those," Buchbinder said.
"With each step we are learning more information that we couldn't get any other way. ... We don't know what it is going to take to make a safe and effective vaccine. Each of these studies, particularly larger trials in humans, help shine a light on issues that we didn't know or understand before" (Lyn, 10/20).
The New York Times examines how the results of the Thai HIV vaccine trial may help guide future studies. Though "the vaccine's protective effect might be even weaker than researchers first admitted ... the complicated six-shot, two-vaccine regimen may have briefly worked better in the first year after it was given, and also may have worked better in Thais at average risk from heterosexual sex, rather than those who used drugs or men who had sex with men. Those offshoot results could open avenues for future research, scientists said" (McNeil, 10/20).
"Researchers hope that careful studies of participants' blood samples may help tease out exactly which immune responses protected people in the vaccine group, information that could be used to design better vaccines," Science's blog, "ScienceInsider," reports. "One of the field's major frustrations has been its inability to find so-called correlates of protection, or biological markers for immunity. 'This study is now really the only hope we have of finding them,' says HIV researcher Joep Lange of the Academic Medical Center in Amsterdam." The blog includes information about plans for follow-up studies.
"Given the string of disappointments in their field, AIDS vaccine researchers say they're counting their blessings today," the blog writes. "If this were any other vaccine you'd say these are incredibly disappointing results," Bruce Walker of the Massachusetts General Hospital said. "Here you see a signal that looks to me like it's marginal -- and that's exciting" (Enserink/Cohen, 10/20).