“It’s a really exciting time to be in AIDS research,” he explained. He was talking to an audience Wednesday evening at the George Washington University Marvin Center in Washington, DC, on “HIV Transmission and Prevention of Transmission: Working Toward the End of the AIDS Pandemic,” in a talk hosted by DC CFAR, the District of Columbia Developmental Center for AIDS Research.
Cohen, the principal investigator of HPTN 052, the study that proved the value of HIV treatment in preventing transmission of the virus that leads to AIDS, plays a big part in why it’s an exciting time in his field. Heralded as Science magazine’s scientific breakthrough of 2011, the HPTN 052 study showed that immediate antiretroviral treatment for an infected partner in a relationship with an uninfected partner results in a 96 percent reduction in the risk of transmission to the uninfected partner. Recent studies published in Science further confirmed that treatment as prevention is successful in reducing the risk of HIV acquisition on the “real world”, population-level as well.
But it’s far from the only reason this is an exciting time for Cohen who also likes to talk about vaccines, the changes in treatment to come, breakthroughs in continuing to understand how transmission happens and the impact all of that will have on prevention as well as, conceivably, a cure.
“But,” he added, “there are big controversies.” So he was going to talk about where he stands on them, and “exactly what I think everyone should do.”
That includes: “Once a person has been tested as infected, I personally believe they should start treatment.”
This is both the product of his work, and where resources are readily available, the practice, but he provided painstaking back up as well.
“With HIV, the concentration of the pathogen matters,” he said. This is not true of all bugs, he added, giving the example of some noroviruses (“You go on a cruise ship, you vomit,” he offered.)
Waiting for immune cell – CD4 – count to drop to the levels set by current World Health Organization guidelines does not serve patients well, he added.
“Who can say it’s a good idea to deplete your CD4 cells?” he asked. “Nobody. Nobody can say that.”
A reason supplied for doing that, he mentioned, “and I really hate this one,” has been the logistical challenges of putting everyone who tests positive for HIV on treatment. Once, he pointed out, logistical challenges provided the rationale for not putting people in resource-poor environments on treatment at all. “We need to separate financial and logistical concerns from what is the best medical advice,” he said.
Those logistical challenges will change, he said, pointing to changes in treatment since the mid-1990s when a handful of pills constituted treatment as opposed to one pill, which constitutes treatment for some patients now. Treatment may, someday soon, consist of a monthly injectable, he said.
In addition, he cited a Centre for Infectious Disease Research in Zambia (CIDRZ) study recently presented at the CROI conference in Atlanta, showing that people starting on treatment immediately were far less likely to be lost to followup care. And, he pointed out, retaining patients in care is cost effective.
In addition, he said, treatment is a bridge to the time when science produces a vaccine or a cure, both of which he says are attainable.
“I am unbelievably hopeful about vaccine development,” he said.
The RV-144 vaccine trials in Thailand yielded big clues on how to get infected individuals to make the broadly neutralizing antibodies necessary to fight off the HIV virusThe recent disappointing results from the VOICE trials, Cohen said, highlights the need to explore other pre-exposure methods to prevent the spread of HIV. Trials underway for vaginal rings containing antiretroviral drugs, are promising, he said. It’s time to be optimistic about the end of AIDS, Cohen reiterated, but to be wise in this optimism.
“We’ve been here before with syphilis and tuberculosis,” he said, referring to the time when both appeared to be beaten. Instead, both infectious diseases have resurged in drug-resistant forms.
“Don’t be deluded into thinking we’re done,” he said, “Now is the time to redouble our investments.”