Syphilis, once nearly eliminated in the United States, continues to resurge, reaching the highest rate of new infections recorded since 1950, the Centers for Disease Control and Prevention said on Tuesday.
More than 207,000 cases were diagnosed in 2022, the last year for which data are available. That represents an 80 percent increase since 2018, and 17 percent over the previous year’s tally, according to a new C.D.C. report.
The rates soared in every age group, including newborns. In November, the C.D.C. said more than 3,700 cases of congenital syphilis were reported in 2022, roughly 11 times the number recorded a decade ago. The disease caused 231 stillbirths and 51 infant deaths in 2022.
Experts pointed to a slew of reasons for the continued increases in syphilis and other S.T.I.s.
Substance use, which is tied to risky sexual behavior, has risen. With better prevention and treatment for H.I.V., condom use has fallen out of vogue — decreasing by about 8 percentage points between 2011 and 2021 among high school students, for example.
And, crucially, there are far fewer sexual health clinics, along with the disease-intervention specialists and nurses who staffed them.
Syphilis has been increasing even in countries with national health care, because “sexual health services remain inadequate relative to the need pretty much everywhere,” said Dr. Jay Varma, chief medical officer at Siga Technologies and a former deputy commissioner of health for New York City.
“But it’s particularly a problem here in the United States,” Dr. Varma said.
“When you miss one case, you then end up with two more cases, and if you miss two cases, you then end up with four,” he added. “That’s how epidemics grow.”
With more than 84 cases per 100,000 people, South Dakota had the highest rate of syphilis infections, more than double that in New Mexico, the state with the next highest incidence. (Arkansas, Oklahoma and Mississippi rounded out the top five.)
Black Americans comprised about 30 percent of primary and secondary syphilis cases. But with 67 cases per 100,000 people, Native American/Alaska Native people had the highest rates.
“The syphilis epidemic touches nearly every community, but some racial and ethnic groups bear the brunt because of longstanding social inequities,” said Dr. Jonathan Mermin, director of the National Center for H.I.V., Viral Hepatitis, S.T.D. and TB Prevention at the C.D.C.
Left untreated, syphilis can damage the heart and brain, and cause blindness, deafness and paralysis. Infection during pregnancy can lead to miscarriage and stillbirth, and infants who survive may become blind or deaf, or have severe developmental delays.
Chlamydia is a far more common sexually transmitted infection, with nearly 1.7 million cases. Reported diagnoses dropped sharply in 2020 and began picking back up in 2021; the rate in 2022 remained flat.
Gonorrhea had been increasing steadily after a historical low in 2009, but appeared to decline in 2022, dropping to about 648,000 cases from more than 700,000 the year before. The rates decreased across race, sex and age, but the decline was most pronounced among women aged 20 to 24.
But without confirmation that those trends are real, “we shouldn’t be celebrating,” said Dr. Ina Park, an S.T.I. expert at the University of California, San Francisco.
“Those two diseases are often asymptomatic,” Dr. Park said. “If we’re seeing declines in young women, it might be because they’re simply just not being screened.”
The Biden administration has taken several steps in an effort to curb S.T.I.s. Last summer, the Department of Health and Human Services set up a national task force for syphilis, which is focusing on the 14 jurisdictions with the highest rates, according to Adm. Rachel Levine, assistant secretary of the department.
The C.D.C. proposed prescribing doxycycline, a widely used antibiotic, to gay and bisexual men and transgender women who have had unprotected sexual encounters. The Food and Drug Administration has temporarily allowed the importation of an alternative to the syphilis treatment Bicillin L-A, which has been in short supply in the United States.
The F.D.A. has also authorized the first at-home sample collection kit for chlamydia and gonorrhea. And the C.D.C. is helping to develop a simple syphilis test that can be used in clinics within the next two years, Dr. Mermin said.
About 86 percent of syphilis cases were diagnosed outside of sexual health clinics in 2022, Dr. Mermin said. That suggests that controlling the epidemic will require primary care doctors, emergency departments, community health centers, and correctional and drug treatment programs to screen for the infection.
“Wishing hard won’t prevent sexually transmitted infections,” Dr. Mermin said. “We need sustained public health efforts.”
