Diligent public health efforts nearly eliminated syphilis 20 years ago.

Stopping outbreaks involved extensive testing and treatments for the sexually transmitted infection (STI) in affected people, as well as tracing, testing, and treating their sexual partners.

“It’s hard, in-the-trenches work” to control syphilis, said Thomas Dobbs, MD, MPH, an infectious diseases specialist and dean of the John D. Bower School of Population Health at the University of Mississippi Medical Center. “It’s a lot of effort to cut off the branches of an ever-expanding network” of sexual contacts.

As STI clinics have closed and the public health workers have been laid off, syphilis has come raging back, with “catastrophic” consequences for babies of affected mothers, Dobbs told CIDRAP News.

Maternal syphilis rates in the United States tripled from 2016 to 2022 reaching 280.4 per 100,000 births in 2022, according to the Centers for Disease Control and Prevention (CDC).

Cases are rising even more quickly in Mississippi, where the rate of maternal syphilis infections grew more than 1,000% from 2013 to 2023, according to a research letter by Dobbs and his colleagues published yesterday in JAMA Network Open. During that 10-year period, maternal infections in Mississippi climbed from 86 cases per 100,000 births to 1,016 cases per 100,000 births.

Rates of congenital syphilis, which can be contracted in the uterus or during delivery, have risen for 12 consecutive years, with nearly 4,000 reported cases in 2024, according to the CDC.

Mississippi faces particular health challenges, including a high poverty rate and large numbers of people without health insurance. In August, the state declared a public health emergency due to soaring rates of infant mortality.

Syphilis is more common among people with opioid use disorder, as well as those who have been incarcerated or have no health insurance.

In terms of Mississippi’s maternal syphilis infections, “it’s easy to see how we could represent what’s coming for the rest of the country,” said Dobbs, the study’s senior author. “We’re at the leading edge of health challenges.”

Preventable tragedies

Maternal syphilis infections kill up to 40% of infected infants and can cause devastating health problems in those who survive, including blindness, hearing loss, joint pain, bone problems, scarring, and other issues.

Elevated rates of maternal and infant syphilis, which are both preventable, reflect failures of the public health system, Dobbs said.

Infection with syphilis and other STIs can be prevented by using condoms during sex. In most cases, syphilis can be treated with a single shot of antibiotics, Dobbs said. Screening and treating women during pregnancy can protect both mother and child.

In the study, the highest risk of maternal syphilis was found in Black mothers, women aged 24 and under, unmarried women, and those without comprehensive prenatal care. More than one third of mothers with syphilis had no prenatal care in the first trimester of pregnancy, while 4.5% received no prenatal care at all.

Syphilis infections in pregnant women and babies in Mississippi began increasing even before the COVID-19 pandemic forced many STI clinics to close or cut back services. State-wide budget cuts in 2015 closed many clinics and thinned the public health workforce.

Challenges ahead

The new study should be a “public health wake-up call,” according to an accompanying editorial by Robert L. Cook, MD, MPH, a professor of epidemiology at the University of Florida.

Yet budget cuts at the CDC could make it harder to track syphilis cases and hire public health workers, Cook wrote. 

The Trump administration has slashed funding for public health and has closed CDC labs that conducted testing for STIs and hepatitis.

Pregnant women face particular challenges.

In his editorial, Cook noted a national shortage of an injectable form of penicillin that is the only medication approved to treat syphilis in pregnancy. He noted that health departments are alerting health care providers about the shortage and urged them to prioritize its use for pregnant women.

A new treatment regimen—in which people take the antibiotic doxycycline after intercourse—is showing promise in preventing syphilis infections in men. The treatment, known as doxy-PEP, is not considered safe in pregnancy, so experts aren’t recommending it for women, Cook wrote. Studies suggest that doxy-PEP also may increase antibiotic resistance. 

The US Preventive Services Task Force and the American College of Obstetrics and Gynecology both recommend that pregnant women be tested for syphilis.

At least 10 states—Alabama, Arizona, Colorado, Georgia, Maryland, Mississippi, Missouri, North Carolina, Tennessee, and Texas—now require syphilis testing during pregnancy.

Simply testing women in the first trimester of pregnancy isn’t enough, Dobbs said. He has known women who were tested and treated early in pregnancy, then reinfected by the same partner before delivery. That’s why states need to restore the budgets for contact tracing and treatment programs.

“It’s a tragedy to have infants die from a disease that is so easily preventable and treatable,” Dobbs said.