Do Gay Men REALLY have Higher STI rates?

Are We Overlooking Chlamydia in Women?

I'm obsessed with sexual health.

Every single day, 365 days a year, I visit [PubMed.gov] and search for the latest research on gonorrhea, chlamydia, HIV, syphilis, and other sexually transmitted infections.

I read an enormous amount of scientific literature on these subjects. Probably more than is healthy for someone who also has a business to run.

And over the years, I've noticed something.

An extraordinary amount of academic research and public health attention surrounding sexually transmitted infections focuses on men who have sex with men.

Now, there's a perfectly understandable reason for some of this. HIV has historically affected gay and bisexual men disproportionately in the United States. And certain other infections, particularly syphilis and gonorrhea, also have substantial burdens in this population.

But I sometimes wonder whether we've allowed our understanding of HIV epidemiology to influence the way we think about sexually transmitted infections more generally.

Have we simply accepted that gay men have higher rates of STIs than heterosexual women without sufficiently questioning whether that's true for each individual infection?

Because when it comes to chlamydia, I'm not convinced.

Almost a Million Women

According to the CDC's provisional 2024 STI surveillance data, 943,890 cases of chlamydia were reported among American women.

Compare that to 564,489 cases among men.

Not gay men. ALL men.

In other words, approximately 62% of reported chlamydia infections occurred in women.

Now, before anyone points out the obvious, I understand that these numbers don't tell us whether an individual woman is more likely to have chlamydia than an individual gay man.

There are far more heterosexual women than gay men in the United States. We need population-specific prevalence data to make that comparison.

And that brings me to the bigger problem.

How confident can we be in our understanding of chlamydia prevalence when we aren't testing everyone equally?

What Happens to Women After Age 25?

The CDC recommends annual chlamydia screening for sexually active women under 25.

Once a woman reaches 25, however, routine screening is recommended primarily when she has recognized risk factors, such as a new sexual partner, multiple partners, or a partner who has other partners.

Compare that with sexually active men who have sex with men, for whom annual screening is recommended at relevant anatomical sites, with screening every three to six months recommended in higher-risk circumstances.

Consider a 45-year-old gay man taking HIV PrEP. He might be tested for chlamydia four times a year.

Now consider a 45-year-old married woman.

She might see her gynecologist regularly. She might receive Pap smears and HPV screening. She might think she's receiving comprehensive sexual health care.

But she could go a decade without a single chlamydia test.

And remember, a Pap smear doesn't test for chlamydia. It screens for abnormal cervical cells, while chlamydia requires a separate laboratory test.

This becomes particularly interesting when you consider that chlamydia frequently causes no symptoms whatsoever.

If both of these people acquire chlamydia, which infection is more likely to be discovered and reported to the CDC?

Obviously, the one in the person being tested regularly.

This doesn't prove that older women have the same chlamydia prevalence as gay men. Chlamydia really is more common in younger people.

But it raises a question that I think deserves considerably more attention.

Are we measuring who actually has chlamydia, or are we disproportionately measuring the people we've decided to look for it in?

What About Heterosexual Men?

There's actually a third population worth mentioning here: heterosexual men.

According to the CDC's chlamydia screening recommendations, there isn't sufficient evidence to recommend routine chlamydia screening for heterosexual men at low risk.

Think about that for a moment.

A sexually active gay man taking HIV PrEP might be tested for chlamydia four times every year.

A sexually active heterosexual woman under 25 should be screened annually. After 25, routine screening generally depends on recognized risk factors.

And a sexually active heterosexual man might never receive routine chlamydia screening at all.

Three populations. Three dramatically different approaches to finding the same bacterial infection.

Now, that doesn't necessarily mean the recommendations are wrong. Screening recommendations consider numerous factors, including infection prevalence, potential complications, the benefits of detecting asymptomatic infections, and the evidence that screening improves health outcomes.

But these differences create an obvious problem when we're trying to compare infection rates.

If one population is tested four times a year and another is rarely tested, we shouldn't be surprised when we're much better at discovering infections in the first population.

And we certainly shouldn't confuse the number of infections we've discovered with the number of infections that actually exist.

And the Consequences Aren't the Same

Here's another reason I find this so important.

Chlamydia is frequently uncomplicated in men, although it can cause urethritis, epididymitis, and occasionally other serious problems.

For women, the potential consequences of an untreated genital chlamydia infection can be especially devastating.

Chlamydia can ascend into the upper reproductive tract and cause pelvic inflammatory disease.

That can result in permanent damage to the fallopian tubes, infertility, chronic pelvic pain, and an increased risk of ectopic pregnancy.

These aren't trivial complications.

A woman might acquire chlamydia in her 20s, never experience recognizable symptoms, and discover years later that damage to her reproductive system has affected her ability to become pregnant.

The CDC's chlamydia treatment guidelines specifically emphasize the importance of preventing reproductive complications in women.

So even if chlamydia prevalence were somewhat lower among heterosexual women than gay men, that wouldn't necessarily mean prevention should receive less attention.

The severity of potential outcomes matters, too.

Which Brings Me to DoxyPEP

One of the most exciting developments in sexual health has been DoxyPEP.

For those unfamiliar with it, DoxyPEP involves taking 200 milligrams of doxycycline within 72 hours after sex to reduce the likelihood of acquiring certain bacterial STIs.

Clinical trials involving men who have sex with men have demonstrated reductions exceeding 70% in chlamydia and syphilis.

That's remarkable.

And I'm delighted that we have this prevention option.

But here's where things get interesting.

The CDC's 2024 DoxyPEP guidelines recommend that healthcare providers counsel and offer DoxyPEP to men who have sex with men and transgender women who have had a bacterial STI within the previous year.

There isn't an equivalent recommendation for heterosexual women.

A randomized clinical trial involving 449 cisgender women in Kenya, published in the New England Journal of Medicine in 2023, did not demonstrate a statistically significant reduction in bacterial STIs among women assigned DoxyPEP.

However, researchers also found evidence suggesting that MOST participants weren't consistently taking the medication.

Doxycycline was detected in only 29% of the hair samples tested.

There is new evidence that DoxyPEP works well in women.

I Think We Need to Rethink How We Talk About STI Risk

I want to be very clear about something.

This isn't an argument for spending less money researching sexually transmitted infections in gay men.

Quite the opposite.

Research involving gay and bisexual men has produced some tremendous advances in sexual health. DoxyPEP is one of them. HIV PrEP is another.

I want more of that research, not less.

But I also want us to question the assumptions that determine which populations receive the most scientific attention.

Sexual identity is not a pathogen.

Chlamydia doesn't know whether someone identifies as gay, straight, bisexual, or anything else.

It spreads through sexual contact. Actual risk depends on factors such as exposure, sexual practices, partner networks, and the prevalence of infection among partners.

And identifying infection depends on whether we're actually testing for it.

I don't know whether a sexually active 35-year-old heterosexual woman is as likely to have chlamydia as a sexually active 35-year-old gay man with a comparable number of partners.

That's a question I'd genuinely like to see answered using representative data, with appropriate consideration of sexual exposure and testing practices.

But I do know that we diagnosed nearly a million women with chlamydia in a single year, despite routine screening becoming much less universal after age 25.

I know that untreated chlamydia can cause serious reproductive harm in women.

And I know that we have a remarkably effective prevention strategy for chlamydia in DoxyPEP.

None of this means our current public health recommendations are necessarily wrong.

It does mean that some of our assumptions deserve closer examination.

Maybe the most important question isn't why we're paying so much attention to sexually transmitted infections in gay men.

Maybe it's why we aren't asking enough questions about everyone else.

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Scientific References

1. Centers for Disease Control and Prevention. Sexually Transmitted Infections Surveillance, 2024 (Provisional). [CDC STI Statistics](https://www.cdc.gov/sti-statistics/annual/index.html)

2. Centers for Disease Control and Prevention. STI Screening Recommendations. Recommendations for screening women and men who have sex with men. [CDC Screening Guidelines](https://www.cdc.gov/std/treatment-guidelines/screening-recommendations.htm)

3. Centers for Disease Control and Prevention. Chlamydial Infections — STI Treatment Guidelines. Information about complications, reproductive health consequences, and treatment. [CDC Chlamydia Guidelines](https://www.cdc.gov/std/treatment-guidelines/chlamydia.htm)

4. Bachmann LH, et al. (2024).CDC Clinical Guidelines on the Use of Doxycycline Postexposure Prophylaxis for Bacterial Sexually Transmitted Infection Prevention, United States, 2024.MMWR Recommendations and Reports. [CDC DoxyPEP Guidelines](https://www.cdc.gov/mmwr/volumes/73/rr/rr7302a1.htm)

5. Stewart J, et al. (2023). Doxycycline Prophylaxis to Prevent Sexually Transmitted Infections in Women.New England Journal of Medicine, 389:2331–2340. [PubMed — PMID 38118022](https://pubmed.ncbi.nlm.nih.gov/38118022/)

6. Luetkemeyer AF, et al. (2023). Postexposure Doxycycline to Prevent Bacterial Sexually Transmitted Infections. New England Journal of Medicine, 388:1296–1306. [Original Clinical Trial](https://www.nejm.org/doi/full/10.1056/NEJMoa2211934)