Hidden Chlamydia and Gonorrhea: 1 in 8 Men at Community Venues in Five Cities, 2017

Chlamydia and gonorrhea in the rectum or throat — "extragenital" sites — usually cause no symptoms. That lets them linger and spread, may help gonorrhea develop antibiotic resistance, and raises the risk of passing on or catching HIV. Gay, bisexual and other men who have sex with men (MSM) carry a disproportionate share of sexually transmitted diseases (STDs) in the United States — but most of what is known comes from men tested at STD and HIV clinics, who may be at higher risk than MSM generally.

So in 2017, CDC's National HIV Behavioral Surveillance (NHBS) went to where men socialize.

The study

• Where: MSM-frequented bars, clubs, fitness centers and similar venues in five cities — Houston, Miami, New York City, San Francisco and Washington, DC.
• Who: men 18 or older, male at birth and identifying as male, living in the city, who'd had sex with a man in the past year.
• How: an interviewer-led survey, an anonymous HIV test, and self-collected rectal and throat swabs, with small payments for taking part. Positive results went back to local teams for notification and treatment referral, anonymity kept through numeric IDs.

Of 2,371 eligible participants, 2,077 (87.6%) gave swabs; 2,075 had valid results.

What they found

13.3% — about 1 in 8 — had chlamydia or gonorrhea in the rectum or throat.

Image from CDC's report

Who was more likely to be infected

• Younger men: at 18–29, rates were higher than in older men for every infection except throat chlamydia — rectal chlamydia 9.2% vs 3.8% at 50 and over.
• Men with HIV: rectal gonorrhea 8.2% among men who reported being HIV-positive, against 3.3% among those who tested HIV-negative. Throat infections were similar either way.
• Black and Hispanic men had more throat gonorrhea (6.6% and 5.3%) than white men (3.2%); otherwise race made no difference.

A third weren't being screened

698 men (33.6%) said they hadn't had an STD test in the past 12 months. Yet infection rates were about the same whether or not they had been tested.

What it means

• These rates are lower than clinic-based estimates — but still high, which suggests sexually active MSM in general face elevated STD risk, and that clinic figures aren't badly skewed.
• Screen every sexually active man who has sex with men at least once a year, at every site exposed — rectum and throat, not just urine.
• Men at higher risk may need screening every 3–6 months: those already tested had just as much infection.
• HIV care guidance already calls for rectal and throat screening at the first visit and at least yearly for men reporting receptive anal and oral sex — and this study found high rates among men with HIV.
• Better access to culturally competent care, and clinicians following the screening guidelines, are key.

Limits: five cities, not the whole country; venue sampling, not a random sample; no urogenital testing (though most men with an unnoticed urogenital infection also have one elsewhere); and self-reported "STD testing" may overstate proper extragenital screening.

Image from CDC's report

Sources

Based on Michelle L. Johnson Jones, Johanna Chapin-Bardales, Destani Bizune, John R. Papp, Christi Phillips, Robert D. Kirkcaldy, Cyprian Wejnert, Kyle T. Bernstein and the National HIV Behavioral Surveillance Sexually Transmitted Infection Study Group, "Extragenital Chlamydia and Gonorrhea Among Community Venue–Attending Men Who Have Sex with Men — Five Cities, United States, 2017," MMWR, volume 68, Centers for Disease Control and Prevention; a work of the United States government in the public domain.