June 11, 2013
Earlier this year the National Institute of Allergy and Infectious Diseases ended the HVTN 505 exploratory clinical trial, intended to test whether that vaccine could either prevent HIV infection and/or reduce the amount of HIV in the blood of vaccine recipients who became infected later. Sadly, the vaccine failed to reduce the viral load of participants who became infected with HIV, and greater numbers of people who received the vaccine than received a placebo became infected later.
Wayne C. Koff, Ph.D., is senior vice president and chief scientific officer at the International AIDS Vaccine Initiative--a global nonprofit fighting to ensure the development of safe, effective, accessible HIV vaccines--and an internationally recognized leader in AIDS-vaccine R&D. We asked Dr. Koff about what this setback means for HIV-vaccine research, particularly as it relates to Black people.
First, can you help us understand what a prime-boost vaccine is?
The initial, or prime, vaccine is followed by a booster shot. Researchers believe that after the first vaccine strengthens the immune system, the booster will enhance its effectiveness. This "prime boost" strategy is believed not only to enhance protection from the virus but also to extend protection over a longer period of time.
Did the vaccine increase the participants' risk of getting HIV?
I don't think so, and I say that with a lot of caution, as there will be a lot of analysis of the data.
And so far, I haven't seen any data in any of the trials that would indicate any difference in racial differentiation for risk or benefit for any of the vaccines that have been tested.
Didn't a previous study show a higher rate of HIV infection among people who received the same vaccine?
In 2007 a trial in South Africa that tested a vaccine made by Merck was also halted for the same reasons.
How far back does the HVTN 505 failure set us?
It's certainly a disappointment. We would like to have seen some level of efficacy to build on. It is certainly possible that this type of trial may be seen as too risky moving forward.
What does this suggest for the future of an HIV vaccine?
The work to better understand the results of HVTN 505 is only just beginning. I think what you're going to see now is a group of trial vaccines move into efficacy trials focused on the combination of a vaccine that can produce effective antibodies and effective T cells. At that point we likely will have an effective HIV vaccine.
What role can Black people play in getting us to an effective HIV vaccine?
We are hopeful that as new vaccines become ready for efficacy trials, Blacks everywhere will participate. It is important to get as much information across geographical spectrums, and racial groups, [as possible] to ensure that a vaccine will have been adequately tested for effectiveness in everyone who could receive it.
Glenn Ellis, author of Which Doctor? What You Need to Know to Be Healthy, is a Philadelphia-based health columnist and radio commentator.