Combining a vaccine that is at least 50 percent efficacious with “optimal implementation of existing treatment and prevention modalities” could end the HIV/AIDS epidemic, said Anthony S. Fauci, MD, Director, National Institute of Allergy and Infectious Diseases (NIAID), in a plenary address Thursday at TropMed2017.
Fauci simply but forcefully delivered that dramatic pronouncement about a horrific infection that took he and other infectious disease experts completely by surprise in the early 1980s—and then proceeded to burn mercilessly around the world, killing millions and exacting an especially heavy toll on sub-Saharan Africa.
“I can tell you that it is extremely unlikely that we will get an HIV vaccine that is 98 percent effective, similar to measles or yellow fever or polio vaccines,” Fauci said. “But if you have one with 50 to 60 percent efficacy, together with a combination of protection and treatment, that might be able to do the trick.”
Fauci believes the key to developing such a vaccine could rest with ongoing efforts to identify “broadly neutralizing antibodies”
to HIV and validating them in human trials. But Fauci cautioned that it’s one thing to show that a broadly neutralizing antibody can provide protection and quite another thing to make a vaccine that can induce them
in people. He thinks such a vaccine possible, but that even if all goes well, it’s still several years away.
Fauci also discussed the breakthrough discovery several years ago that found administering HIV drug therapy to uninfected people at high risk of disease—such as the HIV-free partners of infected individuals—is more than 90 percent effective at preventing transmission. It’s an approach known as “pre-exposure prophylaxis”
or PrEP. Fauci noted that there are theoretical models that show you could “shut down the epidemic” by “treating everyone infected and giving PrEP to those at high risk.”
But he believes that the “implementation gap,” in which there are still some 17 million infected people worldwide who are not receiving therapy, is too wide for such an approach to succeed. Fauci said he has concluded that an “HIV vaccine is in fact essential to durably ending the HIV epidemic.”
Still, Fauci said it’s remarkable how far the community has progressed since the summer of 1981, when he and other infectious disease experts were confounded by the sudden appearance of two obscure conditions, pneumocystis pneumonia and Kaposi sarcoma, in gay men in New York, Los Angeles and San Francisco. In those early years, he said, the disease was first known as GRIDS for “gay-related immunodeficiency syndrome,” because the HIV virus had not yet been identified as the cause.
He showed a photo of himself from the winter of 1981-82, making the rounds to see HIV/AIDS patients whose average survival was one to one-and-a-half years. Now, he said, with targeted anti-retroviral therapy, “I can look a person in the eye and tell them that if they take their medication religiously, they can live an additional 50 years.”
“For a person who is 25 years old,” Fauci said, “add 50 years and in the U.S., that is almost a normal lifespan.”