STI Epidemic Slows in US As New Syphilis, Gonorrhea Cases Fall

• Rates of sexually transmitted infections (STIs) appear to be leveling off after decades of growth in the U.S., according to the latest statistics from the CDC.
• STIs remain at record levels, but new cases of chlamydia and syphilis could finally be stabilizing, while cases of gonorrhea have declined for two years in a row.
• Large discrepancies in STIs persist for certain populations, with adolescents, gay men, and Black individuals bearing much of the burden.

Meanwhile, cases of syphilis, including reporting for different stages of the disease and congenital syphilis, continued to grow. Still, there’s been a steep decline in syphilis cases compared to prior years.

More than 2.4 million cases of chlamydia, gonorrhea, and syphilis were reported last year; the vast majority (1.6 million) were chlamydia, followed by gonorrhea (600,00) and syphilis (209,000).

Overall, the total number of STIs decreased by 1.8% between 2022 and 2023.

While new cases of gonorrhea, chlamydia, and syphilis — the three most common STIs — are still at or near record levels, experts are cautiously optimistic about the new CDC data.

“We’re at an inflection point in the epidemic. This report is encouraging in a number of areas, but it also shows that we have a lot of work to do,” Bradley Stoner, MD, director of the Division of STD Prevention at the National Center for HIV, Viral Hepatitis, STD, and TB Prevention at the CDC, told Healthline. “We still have a lot of STIs in the U.S., and they’re not equally distributed,” he said.

The data confirms discrepancies in disease burden, Stoner noted. Rates of STIs are not equally distributed, with certain groups, including gay and bisexual men, Black people, and young adults (ages 15-24) disproportionately affected.

Syphilis, an STI that can lead to serious health problems, including nerve and brain damage remains the most pressing concern for doctors, and particularly congenital syphilis, which is when the disease is spread to a baby during pregnancy.

In 2023, cases of syphilis increased by 1%, marking more than a 10% decrease compared to the prior year, and the first substantial decrease since 2001.

But, the U.S. still reported nearly 210,000 cases, the highest number since 1950.

“I think the most important part of the report is the fact that we’ve seen a decline in the growth of syphilis cases. The fact that the overall syphilis rate only ticked up by one point. This is really profound,” David Weismiller, MD, ScM, professor of family and community medicine for the Kirk Kerkorian School of Medicine at UNLV, told Healthline.

There were also nearly 4,000 reported cases of congenital syphilis reported in 2023, the largest number of cases since 1992. Among those cases, 279 resulted in congenital syphilis-related stillbirth and infant death.

Jake Scott, MD, clinical associate professor of infectious disease at Stanford Medicine, called the congenital syphilis statistics “alarming.”

“Congenital syphilis should never, ever occur. No child should die from syphilis. It’s so easy to prevent,” Scott told Healthline.

Gonorrhea, a sexually transmitted infection caused by the bacterium Neisseria gonorrhoeae, is spread through genital contact and bodily fluids.

This STI can infect the genitals, as well as the rectum, eyes, throat, mouth, and female reproductive tract. While it may be asymptomatic, common symptoms of gonorrhea may include painful urination and discharge from the penis or vagina.

The disease fell to historic lows in 2009, but subsequently climbed for more than a decade. The CDC data shows that 2023 marks the second straight year of decline in the U.S.: gonorrhea decreased by 9.2% between 2021 and 2022 and 7.7% from 2022 to 2023.

Chlamydia, also a bacterial STI, is often asymptomatic, but left untreated can cause permanent damage to a woman’s reproductive system, making it difficult or impossible to become pregnant. Symptoms may include painful urination and discharge.

Cases of the disease have been on the rise for roughly two decades, except for a brief, unexplained dip between 2011 and 2013.

Chlamydia cases declined during the COVID-19 pandemic, as did rates of other STIs, but subsequently rebounded. Experts believe the dip has more to do with a lack of sexual health resources at that time, including disease screening, rather than changes to sexual behavior.

“Society opened back up and STIs rose to beyond pre-COVID levels. What we think happened there was a lack of clinical care, because STI clinics were closed for the most part,” Stoner said.

The latest data indicates that chlamydia has returned to pre-pandemic levels, but, the authors of the CDC report warn, this may be an artifact of reductions in chlamydia screening.

It’s too early to tell whether 2023 will signal a renewed downtrend for STIs in the U.S. or not. Experts emphasized the need for more resources, particularly for STI education and screening, and safe sex practices.

“One of the goals of our field is to destigmatize STIs so that people aren’t afraid to ask for the tests that they want or need and for clinicians to have those discussions with their patients,” Stoner said.

Scott said while the report is “encouraging,” discrepancies in care need to be addressed.

“Nearly half of STI cases were in people ages 15 to 24, and so that’s clearly a sign that we are failing to provide effective sexual education to those ages. We aren’t providing enough resources in terms of not only education, but routine testing and treatment,” he noted.

“It’s basically like the morning-after pill for sexually transmitted infections…And it’s clearly quite effective at lowering rates of gonorrhea, chlamydia, and syphilis,” Scott added.

“STI are oftentimes spread without any awareness and without any symptoms. So, for that reason, when people are sexually active, especially if they’re sexually active with multiple partners, and if they’re not using barrier protection, meaning condoms, then regular screening tests are essential because that’s going to be the only way to diagnose,” Scott said.

The three most common STIs in the U.S. — chlamydia, gonorrhea, and syphilis — remain at or near record levels, but could be leveling off, according to a new CDC report.

The data show that 2023 marked two years of declining cases of gonorrhea and chlamydia that since returned to pre-pandemic levels.

Syphilis and congenital syphilis remain alarmingly high, however the number of new cases in 2023 only grew by 1%, representing about a 10% drop from the year prior.

Condom usage (or other barrier protection) and regular screening remain the two most effective tools for STI prevention.