HIV Prevention (PrEP)and the Spike in STI Rates

Is PrEP causing a wave of new STI infections?

M. J. Murphy
13 min readMay 10, 2018
Truvada (a PrEP drug) | Source: NIAID | CC0 Public Domain license/Wikimedia Commons

Critics said Truvada was a “party drug” that would lead gay men to abandon condoms. They might be right. Should we care?

I. Alarmists gonna alarm

In late 2017 the U.S. Centers for Disease Control and Prevention reported (non-HIV) sexually transmitted infections (STIs) had reached a historic high — 2 million new cases in 2016, with a disproportionate number among men who have sex with men (MSM), including gay and bisexual men.

Of 28,000 new syphilis cases, over 80% were MSM, as were nearly 40% of the 470,000 new gonorrhea infections — and the strains of gonorrhea infecting MSM were more likely to be drug-resistant. MSM also made up more than their fair share of the 1.6 million new chlamydia infections. Young, rural, poor, Black, and Hispanic guys were especially hard-hit.

Source: CDC

The CDC report generated a predictable wave of finger-pointing aimed at PrEP. PrEP (short for Pre-Exposure Prophylaxis) is an HIV-prevention strategy that involves taking HIV-treatment medications before exposure to the HIV virus. With PrEP drugs already on board, even if HIV enters the body, the virus can’t reproduce and is handily wiped out by the immune system.

Currently, the only drug approved for use as PrEP in the U.S. is Truvada, but other drugs are currently in testing and generics are available overseas. A number of studies have shown Truvada can reduce the risk of HIV transmission by up to 99% in men who have sex with men (MSM) and transgender women.

When Truvada for PrEP was first approved by the FDA, some HIV/AIDS activists and prevention specialists started talking about “The End of AIDS.” Finally, there was medicine that could prevent HIV infection before it started. No new infections would mean an eventual end to the HIV/AIDS pandemic.

PrEP drugs don’t require the knowledge or cooperation of sexual partners, and it was forgiving if used imperfectly (unlike condoms, which MSM don’t use consistently and are only 86% percent effective at preventing HIV.)

But critics called Truvada a profit-driven sex toy for rich Westerners” and a party drug that would lead gay men to abandon condoms and engage in riskier sex, resulting in a new wave of HIV transmissions. The “canary in the coalmine” would be an epidemic of STIs among gay men — just like the early 1980s, at the dawn of the AIDS crisis.

Understandably, PrEP critics saw vindication in the CDC’s report on historic STI rates.

Were they right?

Source: Owen Kemp via Unsplash

II. PrEP-sters gettin’ busy

The emergence of a new HIV-prevention strategy like PrEP is like catnip to researchers looking to make a name in a crowded field like HIV/AIDS science. Thus, there have been several international studies looking at the effectiveness of Truvada for PrEP.

Some PrEP studies also looked at what sexual health researchers call risk compensation: behavioral changes in response to perceptions of risk. In other words, they asked: Does a PrEP user’s belief they are at reduced HIV risk lead to changes in sexual behavior, which then increases risk for contracting other STIs (like syphilis, chlamydia, and gonorrhea)?

Risk compensation in PrEP studies is typically gauged by self-reported frequency of sex, numbers of partners, preferred sexual role, and condom use, and through regular testing of study participants for STIs.

Despite sensationalist news reports, evidence of risk compensation by PrEP users is, at best, inconclusive.

The landmark 2010 iPrEx study included 2500 MSM and transgender women living in six different countries. During the study, participants engaged in less risky sex (fewer partners; more condom use) and there was a decline in numbers of STIs over the course of the study. In a 2014 extension of the main iPrEx study, syphilis rates actually declined almost four-fold.

However, in the 2015 IPERGAY study of 400 MSM and transgender women in France and Canada, 35% of participants were diagnosed with a new STI during the study even though there was little change in sexual behavior (amount of sex, numbers of partners, condom use). A 2017 extension of the main IPERGAY study saw 43% of study participants diagnosed with a new STI.

In early 2018, a study of 195 MSM in Montréal reported a 72% increase in STIs among PrEP users (compared to STI diagnoses in the prior year). Rates of rectal chlamydia infections more than doubled (suggesting an increase in anal sex without condoms). High STI rates have also been reported among PrEP users at health clinics in Seattle, San Francisco, and Los Angeles.

It’s difficult to draw simple conclusions from all the studies on PrEP and STIs. Some PrEP users engaged in risk compensation (more sex, more partners, less condoms) —some didn’t. Often, PrEP users were diagnosed with more new STI infections — but not always.

That said, many PrEP studies reflect the findings of a 2016 meta-analysis of previous PrEP studies that found MSM on PrEP were 11 times more likely to acquire chlamydia, 25 times more likely to acquire gonorrhea, and 44 times more likely to acquire syphilis than MSM not on PrEP.

A 2018 meta-analysis came to similar conclusion: in scientific studies to-date, PrEP use is associated with more condomless sex and increased diagnosis for STIs.

This would seem to confirm the dire predictions of PrEP opponents: PrEP use leads to higher STI rates.

But, does it?

Source: Joshua Coleman via Unsplash

III. All is not as it seems

Even if PrEP is associated with more STIs, that’s a far cry from proving that PrEP is the cause. That’s because science doesn’t take place in a vacuum and human sexuality is a complicated thing (to say the least).

When thinking about the findings of PrEP studies, it’s important to bear in mind:

  • PrEP studies attract and enroll those with the greatest STI/HIV risk. One indicator of that is a history of STIs — sometimes numerous previous infections. In fact, participants often had a high rate of STIs at the start of a study. That suggests a history of sexual behavior that puts them at greater risk for STIs, which is what makes them great candidates for PrEP. It’s not surprising, then, that many study participants were diagnosed with new STIs during the time they were using PrEP as part of a PrEP study.
  • PrEP uptake drives STI diagnosis, treatment, and reporting. Current PrEP protocols call for initial and quarterly testing for STIs, HIV, and kidney function. Regular testing detects and treats STIs early — even before they’re symptomatic. But PrEP-driven testing can artificially inflate STI numbers in the short term, as those already prone to STIs are diagnosed and treated. Regardless, mathematical modeling predicts regular STI testing as part of PrEP will gradually lower the overall rate of STIs over time.
  • STI rates were increasing before Truvada was approved for PrEP in 2012. In the U.S., syphilis rates started rising in 2002; chlamydia infections have been up since at least 2002; gonorrhea rates started increasing in 2009. Also, gay men started abandoning condoms as early as 2005 for a variety of reasons: personal preference, desire for greater intimacy, own or partner’s HIV status, whether sexual partner is main or casual, and sexual role/position.
  • STI rates have been highest where PrEP uptake is lowest. PrEP was approved in 2012 — but that didn’t lead to mass adoption. (In May 2018, Gilead, the maker of Truvada, told investors 167,000 people in the U.S. were on the drug; the CDC says 1.1 million should consider it.) PrEP uptake has been the highest on the West Coast, in New England and Mid-Atlantic states, in Florida, and the Upper Midwest. But 7 of the 10 states with highest STI rates are in the South — a region that also has some of the highest HIV rates.
STI rates (per capita) | darker=higher (Source: CDC)
Rate of PrEP use (per capita) | darker=higher (Source: AIDSVu)

So, there’s a number of reasons (some) PrEP users might have higher STI rates and most of them have nothing to do with being on PrEP.

Does that mean higher STI rates are nothing to worry about?

Yes and no.

Source: Pixabay | CC0 Public Domain license

IV. The false equivalency of STIs

a. Yes, we should worry!

Despite their higher STI rates in some PrEP studies — and the scurrilous meme “Truvada whore” that trended on social media — we need to resist thinking about PrEP users as inherently “diseased” or “risky.”

PrEP users include MSM, heterosexual women and men, transgender women and men, sex workers, etc. Just because someone’s on PrEP doesn’t mean they’re having lots of sex with lots of partners…at least, no more than they were before they started. Their number of partners, frequency of sexual activity, preferred sexual position, and partners’ sexual health will vary.

Similarly, we cannot assume that PrEP users have also abandoned condoms — some will continue to use them for STI and pregnancy protection.

But neither should we ignore the anecdotal and scientific evidence that some PrEP users intend to (and, apparently, do) engage in risk compensation: more sex, with more partners, and/or fewer condoms. And when they do, they can both contract and transmit STIs (much like anyone else).

And it’s important to remember that having an STI is a risk factor for HIV. Some STI symptoms (syphilis sores, genital warts, mucous membrane inflammation, etc.) can make it easier for HIV to pass between sexual partners.

That’s why it’s common for a syphilis, gonorrhea, or chlamydia diagnosis to be accompanied by an HIV-positive diagnosis. In the fall 2017 CDC STI report (mentioned at the top of this story) nearly half the MSM with new syphilis infections were also HIV-positive.

Primary and Secondary Syphilis — Reported Cases by Sex, Sexual Behavior, and HIV Status, 2016. Source: CDC.

But while a syphilis infection might pose little health risk to PrEP users — because they’re regularly tested and treated for STIs — the same isn’t necessarily true for their sexual partners.

And that’s because their partners may not also be on PrEP.

(In fact, given the slow pace of PrEP uptake, the odds are they won’t be.) If a non-PrEP using sexual partner contracts syphilis from a PrEP-using sexual partner, their HIV risk increases (even if their PrEP-using partner’s HIV risk is very small).

The health implications of syphilis, chlamydia, and gonorrhea will be different for different people — and PrEP use is one factor in that.

When PrEP is asymmetrical between sexual partners or in sexual networks, HIV risk is also asymmetrical!

The fix, of course, is greater adoption of PrEP by those at risk for HIV. Regular testing and treatment of PrEP users, as part of a PrEP regimen will, eventually, slow the rate of STIs in MSM. More importantly, it will also slow the spread of HIV.

But, in the short term, the slow uptake of PrEP might mean that increased rates of STIs (among PrEP users) may contribute to both STI and HIV risk (in non-PrEP users).

In the U.S., this ‘outsourcing’ of risk will disproportionately be borne by Latino, African-American and under-25 MSM — demographics over-represented among new HIV infections but least likely to be on PrEP.

U.S. population, PrEP use, and HIV infections (by race/ethnicity) (2015). Light blue = whites; purple = blacks; dark blue = Hispanic. Source.

b. Worry? No, don’t be a drama queen!

What PrEP detractors seem to forget when pointing to the many research studies showing higher STI rates among PrEP users is that all — ALL — those studies show PrEP is highly effective at preventing HIV transmissions.

Rather, anti-PrEP-sters talk about HIV and other STIs like they’re fungible commodities: one is just as good…er, bad as another. But they’re not. When we talk abut PrEP and STIs, we need to maintain some perspective.

Because not all STIs are created equal!

Global AIDS estimates by region. Source: WHO.

Globally, an estimated 35 million people have died of AIDS-related illnesses and more than 36 million are currently living with HIV. In the U.S. nearly 700,000 have died; 1.1 million are living with HIV.

In the U.S., new HIV diagnoses are on the decline but roughly 70% of all new diagnoses are among MSM. African-American and Latino/Hispanic MSM make up a disproportionate number of those HIV diagnoses.

New HIV infections by risk group (2008–14). Source: CDC.

And, although we’re encouraged to think of HIV as a chronic manageable illness like diabetes or high cholesterol, living with HIV and HIV-treatment drugs is no picnic.

Unlike HIV, bacterial STIs — syphilis, chlamydia, and gonorrhea — are easily cured with low-cost antibiotics, despite scare-mongering headlines about drug-resistant “super-bugs.”

By contrast, a lifetime of anti-retroviral drugs and medical monitoring is very expensive and burdensome for those living with HIV.

That burden helps explain why 7,000 people still die of AIDS-related illnesses in the U.S. every year. Many were ‘lost to care’ due to the burdens of HIV stigma, poverty, homelessness, depression, and lack of family or community support.

Even those with privilege and means cannot escape the social, psychological, and physical costs of living with HIV.

The sheer scale and scope of the HIV/AIDS pandemic puts the disease in a category by itself. Speaking of it in the same breath with STIs like syphilis, gonorrhea, and chlamydia feels like willful ignorance.

Or some special kind of insensitivity to vastly different scales of human suffering.

Discouraging a prevention strategy with a proven ability to reduce new HIV transmissions and the potential to end AIDS is unfeeling, inhumane and immoral.

That some of the opposition to PrEP is coming from agencies and activists (purportedly) dedicated to ending HIV/AIDS is truly perverse…

Evan J. Peterson, “Truvada Selfie” (2017) | Own work| CC BY-SA 4.0 license. Source: Wikimedia Commons

V. The ‘side effects’ of PrEP

Most pharmaceutical drugs and medical procedures come with side effects — sometimes serious side effects.

Allergy drugs can cause drowsiness; chemotherapy often produces hair loss; surgery sometimes ends in death. Knowing this, patients and doctors weigh known side effects against potential benefits before deciding on a course of treatment.

Sometimes, side effects — even serious ones — are an acceptable price to pay for a potentially life-saving cure.

Thus, rather than asking, “Is PrEP behind the spike in bi and gay men’s STI rates?” we should be asking:

Is a temporary spike in curable STIs an acceptable ‘side effect’ of an HIV-prevention strategy — PrEP — with a proven ability to slow HIV-transmission rates and the potential to end AIDS as we know it?

And in answering that question, we need to be honest about the different health implications of higher STI rates. For PrEP users, they might only mean a short course of antibiotics; for those not on PrEP, they can mean increased HIV risk.

But if our answer is “yes” — higher STI rates are an acceptable short-term side-effect of PrEP — we need to work as hard as possible to increase awareness, access, and affordability of PrEP.

Slut-shaming gay men who take steps to protect themselves, their partners, and their communities against HIV has no place in that effort.

Addendum: I want to offer some response to critiques I’ve received on this story.

  1. U.S. bias: this story’s original brief description of PrEP did not adequately indicate that the brand-name drug Truvada is the only one currently approved for use as PrEP by the FDA in the United States. However, several chemically-identical generic drugs are available internationally and can be legally imported to the U.S. with a valid prescription. Those generics are used widely outside the United States for PrEP. Important distinction: PrEP is an HIV-prevention strategy that involves taking a prescription drug, counseling, being regularly tested, etc. Truvada is a brand-name drug that can be taken as part of a PrEP regimen. The story has been edited to make these facts clearer. Readers wanting to know more about PrEP drugs and regimens can follow the story’s links to some useful web resources.
  2. The headline “Typhoid Marys?”: admittedly I chose this headline for its click-bait value but also because I thought it clever. Everyone wants their published writing to be read and eye-catching headlines are key to attracting readers. However, the most important part of this headline is the question mark, which I used to indicate that I was questioning the validity of the two words that precede it. In other words, the headline is intended to succinctly pose the larger question: “Are PrEP users responsible for the spike in bi/gay men’s STI rates, as PrEP detractors have claimed?” That question is more fully articulated in the block quote following the first image, and even more fully in throughout the first major section of the story. The story that follows is an attempt to answer that question. (Answer: we don’t know for sure but that doesn’t mean we shouldn’t care.) But the question mark in the title is also an attempt to unsettle the insinuation of PrEP opponents: that PrEP is the cause of higher STI rates; that gay men are “typhoid marys.” But I understand the headline’s subtlety might have been lost on some, who thought I may have been accusing PrEP users of intentionally spreading disease. Or that I was recycling a derogatory term once aimed at people living with HIV. I am not. (The story’s not about people living with HIV; it’s about the relationship between PrEP and U.S. bi/gay men’s STI rates.) Hopefully the body of the story sufficiently conveys my position on the question broached (however in-artfully) by the headline. — mm (12May2018)

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Michael J. Murphy, PhD, is Associate Professor of Gender & Sexuality Studies at the University of Illinois Springfield. He is the author of many book chapters, and encyclopedia and journal articles. Most recently, he edited Living Out Loud: An Introduction to LGBTQ History, Society, and Culture (New York: Routledge, 2019). He tweets @emjaymurphee.

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M. J. Murphy

Professor of Gender & Sexuality Studies, Univ. Illinois Springfield