Pre- and Post-exposure Prophylaxis in HIV

Peter L. Salgo, MD: Now, in 2017, where are we in terms of disease prevention? How do we prevent this disease in the first place? Pre-exposure prophylaxis, how do we deal with that?

Eric S. Daar, MD: We spend a lot of time with voluntary counseling and testing. We have invested billions of dollars in the richest country in the world, and the number of new infections is estimated to be, essentially, unchanged in the United States over the last decade or more.

Peter L. Salgo, MD: So, you’re saying it’s a bust?

Joseph Eron, MD: It’s starting to come down.

Eric S. Daar, MD: You could argue that it could have been a lot worse had we not made the investment—but it wasn’t enough if we’re still having 40,000 to 50,000 new infections a year. So it wasn’t enough. People started looking at biologic ways to manage this that doesn’t require, entirely, people-changing behavior. We always look to vaccines, and so far, vaccines have been a bust.

Then, the next big step, and we actually learned this over 20 years ago in preventing pregnant women from transmitting HIV to their baby, is using antiretrovirals. And the big advancement that has had a big impact, globally, is the recognition that when we treat somebody with HIV and suppress their virus, the risk of them transmitting to their partner is extraordinarily small.

Peter L. Salgo, MD: That’s because the actual particle count is nil.

Eric S. Daar, MD: Exactly. That’s been, by far, the biggest advance in prevention. It is virtually 100% protective, based on the data that’s available (if somebody is on therapy and their virus is suppressed).

Paul E. Sax, MD: In fact, in several cities where a high proportion of people are on therapy, the number of new infections has dropped.

Peter L. Salgo, MD: Let’s hit on a couple of quick bullet points. For women who are trying to conceive, can they be prophylaxed?

Eric S. Daar, MD: I think there are 2 ways to look at this. So, you’re assuming now that the male partner is HIV-infected and the woman is uninfected and that they’re trying to conceive and have a biologic child. There’s lots of pieces to this, right? Because there are alternative means in which one would accomplish this feat. So, the first step, based on the data that’s available, is that if the male partner’s viral load is undetectable and has been for at least 6 months, the likelihood of them transmitting to the partner should be virtually zero.

Peter L. Salgo, MD: Okay. So, the bullet point on that is you treat the male partner?

Eric S. Daar, MD: That’s the most important.

Ian Frank, MD: By far.

Peter L. Salgo, MD: What about unborn children? Prophylaxis?

Joseph Eron, MD: Well, prevention of HIV from mother to child—we know how to do that. You treat the mother. Treat the mother, treat the mother, treat the mother. I don’t know what it’s like in Massachusetts or Pennsylvania, but in North Carolina, maybe we see 1 or 2 transmissions in the entire state from mother to child.

Peter L. Salgo, MD: That’s remarkable.

Joseph Eron, MD: It’s gone away. Pediatric HIV is done.

Paul E. Sax, MD: It’s amazing.

Peter L. Salgo, MD: I would like to point out that when I said it was a bust, that was before you said that. That’s huge.

Paul E. Sax, MD: People who specialize in pediatric HIV need to find a new specialty.

Joseph Eron, MD: The whole network needs to find a new thing to do.

Paul E. Sax, MD: I will say one thing. There is still an open research question as to what the safest treatment is to give to pregnant women. We can prevent transmission of HIV, but the babies born to HIV-infected moms who don’t have HIV themselves appear to have health issues. We’re not sure whether it’s that they’re getting some toxicity from the drugs or something else.

Joseph Eron, MD: I know it’s brief—pre-exposure prophylaxis (PrEP). We have to mention PrEP because there may be a lot of people out there listening to this that are primary care doctors. This has to do with what Eric was trying to say: about using antiretrovirals in those very high-risk groups that Ian mentioned—the men who have sex with men and injection drug users, which is going way up. It’s like back in the bad old days. Remember PrEP, right?

Eric S. Daar, MD: And that’s for the masses, right? So, first I talked about what the million or two in the United States can do to prevent from transmitting to their partners. PrEP is really for the millions and millions of uninfected people that allow them to protect themselves.

Ian Frank, MD: And it’s a reason why people may want to volunteer and get tested. If individuals know that they’re at risk for acquiring HIV and if they’re aware that there’s a way that they can prevent becoming infected by taking a pill a day, then that’s incentive to be tested to find out if you’re negative and then to request PrEP.

Peter L. Salgo, MD: Okay. What about post-exposure prophylaxis? And this is of particular interest, of course, to healthcare providers. But it’s also directed toward anybody who suddenly finds out. “Oh my gosh, I was exposed.” What do you do?

Paul E. Sax, MD: We give 28 days (4 weeks) of therapy. In occupational exposures, it makes sense. It probably works. We give it, also, to people who have, for example, sexual assaults. In that setting, I think a lot of what we’re doing is just trying to do something rather than nothing, because often we don’t know the source or if the patient has infection at all. So there’s a tremendous amount of overtreatment for postexposure prophylaxis. Nonetheless, we do it. It is endorsed in the guidelines, and it’s probably one of the reasons why, at least in occupational exposures, there has not been occupationally-transmitted HIV in this country for decades.

Joseph Eron, MD: Decades. The advance is that, now, it’s safe and well tolerated. Twenty years ago you were taking zidovudine (AZT) every 4 hours. You’re vomiting. And now it’s really very different.

Paul E. Sax, MD: You can say there has not been an occupational exposure that has led to HIV acquisition in the United States in decades.

Transcript edited for clarity.