It could be the most promising—and controversial—HIV prevention tool yet. When used correctly, pre-exposure prophylaxis (PrEP), the daily pill that blocks an HIV infection from taking root in the body, can ensure that HIV-negative people stay that way. Combined with other safer sex strategies such as condom use, PrEP transforms the HIV prevention landscape, but not without a dose of scrutiny as well.

What, exactly, is the relationship between PrEP and other risk-reduction strategies like condoms? To understand how a medical doctor thinks about PrEP and discusses it with patients, we spoke to Dr. Christopher Evans, a physician and infectious disease specialist at Oregon Health and Sciences University who works with PrEP patients daily.

Matt Pizzuti: Can you tell me a little about what you do and your expertise in PrEP?

Christopher Evans, M.D.,M.P.H., AAHIVM

Christopher Evans, M.D.,M.P.H., AAHIVM

Christopher Evans, M.D.: I am an infectious disease trained physician, I trained in New York, and now I work at OHSU doing primary care and also infectious disease consultation. Within the clinic that’s HIV care. I also see patients that are at risk for HIV, partners of HIV-positive patients, etc, as well as the public at large.

MP: Who is PrEP recommended for?

CE: PrEP is recommended for anyone who is at risk for HIV; someone who has had possible previous STIs, which may mean you are at higher risk, and high-risk groups, such as someone with an HIV-positive partner, or someone with a partner or number of partners of unknown serostatus (in other words, someone who has sex with people without being able to verify that they are all HIV-negative).

MP: Many of the people currently receiving messages about PrEP are men who have sex with men, and I think it’s sometimes hard for individuals in that category to know whether they, individually, should be considering it. To make this a little simpler, who among at-risk populations would you NOT recommend PrEP for?

CE: First of all PrEP’s not recommended for anyone who’s not going to take it the way it’s prescribed. There also may be people in a long-term monogamous relationship who know the serostatus of their partners and know their partners don’t have HIV. There’s a gray area around monogamous serodiscordant couples (couples with one HIV-positive partner and one HIV-negative partner) when the HIV-positive partner has an undetectable viral load; we know the risk of transmission to the negative partner is low even with unprotected sex. I would add that the CDC still recommends PrEP for serodiscordant couples.

In every relationship everyone has to make their own decisions, though. I’m not there to dictate, I’m there to give you the options and talk about your risk.

In more specific cases, PrEP may not be recommended for pregnant women, although we do know that in some cases some women are pregnant when they get HIV. There are some gray zones for people who have chronic hepatitis B because of the risk of a viral flare-up if you discontinue PrEP.

MP: Out in the community there are a lot of strong opinions about PrEP; it’s pretty common to hear people say that PrEP is being used as an “excuse” to have unprotected sex or that it’s leading to riskier behavior.

At the same time, people in public health roles are saying that PrEP is not a substitute for condoms, although it does make sex much safer if you’re not using condoms consistently. In your view, what’s the relationship between PrEP and condoms?

CE: So there are personal comments, and then there’s evidence. Even in big studies, there’s evidence that the incidence of risky behavior decreases in people on PrEP. The big one was iPrEx, a study on gay, bisexual and transgender women who have sex with men, one of the first that looked at using Truvada for PrEP and was used for FDA approval.

Subsequent studies looked at risky behaviors again and found that risky behaviors, over time, went down, in both those on PrEP and those receiving placebo. But both groups also got safe-sex messages while they are coming in, just as in a patient setting, where it’s not like it’s being just given to people without any counseling.

The analogy I use is, if you have a seat belt would you drive faster? Most people would say they would continue to drive the speed limit even with a seatbelt on because it’s the more prudent thing to do.

Regardless, I always talk to my patients about using condoms. Condom use has a lot of different steps, though, and it’s not just putting on the condom; it’s negotiating using the condom, it’s people going out and having a good time (drinking) and still having the wherewithal to use it, and condoms can break—so condoms as a strategy is not 100% effective because people are not 100% consistent. But I think condoms are a cornerstone of public health policy and still important. I’m not ready to throw them out the door and say you have this other option so we don’t need it anymore.

There’s also the issue that having one STD can increase your risk for others; getting syphilis will increase your risk for HIV. So I’ll talk about the way you can get syphilis or chlamydia or gonorrhea, which can be transmitted through oral sex, anal sex, etc, even while you’re on PrEP.

MP: A lot of us, when we go to get tested, have been counseled on the fact that unprotected oral sex is a safer sex option compared to unprotected anal sex, and that’s mainly because of the risk of HIV. Of course there’s still a risk for transmission of other sexually-transmitted infections. So If somebody is on PrEP, is there still a difference between unprotected anal sex and unprotected oral sex or are they about the same level of risk now?

CE: Anal sex is always going to the riskiest sex, especially if you are the receptive partner or the bottom. You could look at the scale of possible risks for HIV and I’d say that oral sex is at the very bottom, but I don’t think any public health official has said there is no risk for HIV from oral sex—it’s just at the very bottom risk.

MP: Right, but when it comes to other STIs—syphilis, gonorrhea, chlamydia—is there a difference between unprotected oral sex and unprotected anal sex? Most of the population that PrEP pertains to was already at risk for other STIs because, whether or not it’s ill-advised, very few people use condoms for oral sex.

And here’s why I mention that. One concern I see brought up again and again in the community is this idea that PrEP is driving a spike in sexually-transmitted infections because people are getting on PrEP and no longer using condoms. But one thing I’m not sure about is whether the increase in STIs is in the same population as PrEP users, and if unprotected anal sex would make all that much difference when most were already at risk for those infections through oral sex.

CE: I don’t know because there hasn’t been studies done. I don’t think anyone has explained the recent increase in STI rates and I don’t think anyone has linked it to PrEP. That would be a great study to be done, but at this point, nobody knows that to be the case.

For more information about PrEP or first steps if you are interested in getting on PrEP, email Find Dr. Christopher Evans’ info at OHSU here

Tagged on: