Director, Infectious Diseases at UNC-Chapel Hill
I think the biggest challenge is scientific, unequivocally. The challenge is which road to pursue. Which of the things that are increasingly visible to us -- neutralizing antibodies and antibody-dependent cell-mediated cytotoxicity (ADCC) -- have a greater probability of being successful in preventing HIV with urgency?
The second issue is clinical trial design. You have to really think hard about the clinical trial design. If we make a vaccine designed to induce the response that we think is most likely to protect humans, how do we get the credible answer as fast as possible? And while we're doing that, we really need to understand surrogates of immunity. If you start injecting people with a vaccine, and you fail to see the surrogates of immunity on which it's based, you might want to have that as one of the considerations.