Now that effective therapies for active HIV infection are broadly available, there should be renewed focus on basic science regarding HIV, said experts contacted by MedPage Today.
Without it, they worried, there will be no further clinical advances, such as a truly effective HIV vaccine.
"For quite some time, the bulk of the key science in this field has been over. The disease is well-treated and we can prevent everyone from getting it [with pre-exposure prophylaxis], but do you want your children treated with PrEP? These are powerful drugs," Robert Gallo, MD, co-founder and director of the Institute of Human Virology at the University of Maryland School of Medicine in Baltimore, told MedPage Today. "The only answer is a preventive vaccine."
An HIV vaccine has been the holy grail of AIDS research for a number of years. One trial for a HIV vaccine candidate (HVTN 702) is currently ongoing in South Africa. A second vaccine candidate had promising safety and immunogenicity results presented at the International AIDS Society Conference on HIV Science last year. The authors noted that while they have proven the vaccine candidate was safe, a clinical trial has yet to prove that the vaccine could prevent HIV infection. To outsiders, the HIV vaccine effort may be most notable for its high-profile failures.
"All of the successful vaccines against acute virus infections are against relatively simple viruses" that lack the "variability of HIV," Gallo pointed out, which has made vaccine development uniquely challenging. (Although influenza is also highly variable yet is considered vaccine preventable, the variability requires reformulating the flu vaccines every year -- and the stakes of vaccine failure are lower.) In addition, Gallo said, HIV vaccines must avoid over-activating T cells while trying to make the vaccine work.
Instead, Gallo argued that the HIV research field is "getting more clinical."
"That doesn't mean that it's not important, but we're not seeing any real major advances," he added.
"In the earlier days, when the virus was identified, we did a lot of research to understand the virus better -- how it reproduces itself, how it damages the host -- all of which was essential for developing the therapies that have worked so well," Paul Volberding, MD, director of the University of California San Francisco's AIDS Research Institute, told MedPage Today.
He said most of the basic science now has been devoted to vaccine development or to finding a cure, and "we're not developing many new drugs."
"I think that might be dangerous, because I think we could probably still understand more about this virus if we could do some more truly basic discovery of science, which is not really happening," he said.
Michael Saag, MD, of the University of Alabama at Birmingham, said he shared Gallo's "passion for a vaccine," but also saw value in "implementation science" and operations research.
"We need to declare victory in a lot of space, like antiretrovirals and their ability to create what I call a functional cure. And for something like PrEP, we don't need any more studies to show if somebody takes PrEP they're not going to get infected -- we've proven the efficacy," Saag told MedPage Today. "The effectiveness is how do you play that out in the real world."
Unfortunately, the real world beyond PrEP and antiretrovirals has had few success stories. Gallo said that cases such as the so-called "Berlin Patient" did not lead to more advances in research because that was a "freak approach" that cannot be copied in terms of a cure.
"He's lucky he had leukemia, lucky there was a [CCR5∆32] mutant donor sitting around waiting, and lucky he didn't die of total body radiation, but there was no new principle learned there," he said.
Even if there were more interest in vaccine development, a number of roadblocks still exist, Gallo said -- including interest among researchers, and the biggest one of all: funding.
"There's no money for it, but there is money for therapy," he noted. "We should be trying to get a successful preventive vaccine -- the question is whether or not it's doable. But we should always continue the research."