A sharp increase in syphilis cases has led the state of Colorado to declare a congenital syphilis epidemic effective April 25. It requires all health care facilities in the state – from clinics to major hospitals – to offer syphilis testing at least three times surrounding pregnancy: in the first and third trimesters and then at admission for delivery.

State law already requires health care providers to do syphilis testing during the first trimester; a new bill would require it in the third trimester also. The cost of the tests will be covered by insurers and Medicaid, state officials say.

Pregnant women will be offered syphilis testing regardless of the type of appointment – an urgent care visit for a sprained ankle would apply.

“We hope to save many babies from death and suffering,” Colorado Gov. Jared Polis said at a news conference announcing the congenital syphilis epidemic.

The dire consequences of congenital syphilis

The vast majority of syphilis cases are spread through sexual contact. But congenital syphilis happens when the bacterial disease transfers from mother to fetus in utero. The disease brings roughly 40% mortality rates through late-term miscarriage, stillbirths, and deaths shortly after birth.

The 60% of babies who survive can have bone damage, severe anemia, enlarged liver and spleen, jaundice, nerve problems causing blindness or deafness, meningitis, or skin rashes, according to the U.S. Centers for Disease Control and Prevention.

Good prenatal care usually catches syphilis cases, so congenital syphilis disproportionally impacts disadvantaged populations, particularly the incarcerated and among those experiencing homelessness.

“Treatment of mom during pregnancy can definitely help improve outcomes for babies,” said Dr. Helen Dunnington, OB/GYN medical director at UCHealth Greeley Hospital and the hospital’s medical director of Women’s Services. “If untreated, then their baby is at more risk of having congenital syphilis. But if mom gets treated, then you can decrease that risk of vertical transmission.”

Congenital syphilis cases are typically treated with one or more injections of the antibiotic penicillin G benzathine (brand name Bicillin), which is in short supply nationwide.

Dunnington says UCHealth is reserving the drug for syphilis cases. In addition, the U.S. Food and Drug Administration is temporarily allowing the importation of Extencilline, a French-made penicillin G benzathine formulation approved in other countries but not the United States.

Syphilis case counts are skyrocketing

Colorado saw 50 congenital syphilis cases in 2023, up from 32 cases in 2022 and seven cases in 2018. Even the 2018 figure represented a big jump: Just 15 Colorado cases were reported in total from 2003 through 2017. That’s 10 fewer than the number of cases reported so far this year, which, without intervention, is on track to reach 100 to 150 cases in 2024, says Scott Bookman, the state health department’s senior director for public health readiness and response.

“We are experiencing a national crisis regarding syphilis and congenital syphilis, and we are part of that in Colorado,” Bookman said.

Syphilis testing is a start, but it must be followed up with better health care options for pregnant women, says Dr. Michelle Barron, senior medical director of infection prevention and control for UCHealth and a professor of medicine and infectious diseases at the University of Colorado School of Medicine.

A significant proportion of Colorado moms whose babies had congenital syphilis got no prenatal care, she says. Barron says it’s probably no coincidence that the recent rise in cases coincided with the coronavirus pandemic.

“I think it’s a direct reflection of public health resources being channeled into Covid during the pandemic at the expense of other disease interventions,” she said. “Many people are behind on or don’t have access to routine health maintenance screening visits which could help detect cases.”

Three stages of syphilis

Syphilis manifests in three main stages. Primary syphilis comes after initial infection, with painless open sores that last three to six weeks. Untreated, it can soon become secondary syphilis, which typically brings skin rashes and can come with fever, muscle aches, fatigue, patchy hair loss, and other symptoms.

If still untreated, tertiary syphilis can develop after a latent period (that is, no symptoms at all) that can last for years or even decades. Tertiary syphilis develops in about 35% of untreated patients and can come with serious neurologic, heart, eye, ear, and other problems.Many don’t realize they are at risk, and they may not have any obvious symptoms, so screening is an important aspect of detection and allows for treatment, Barron says.

Treatment for primary syphilis typically involves one injections of penicillin G benzathine  antibiotic; secondary and latent syphilis usually takes three injections with at most nine days between injections, Dunnington says.

“Otherwise, you have to start over, so really having that follow-up to come back and get your next injection is important,” she says. Tertiary syphilis generally requires hospitalization and intravenous antibiotics.

U.S. syphilis cases peaked in the 1940s before plunging with the introduction of antibiotics, but they’re up nationally from about 114,000 cases in 2018 to 204,000 in 2022, the last year national data is available. The rate of increase is much higher in Colorado. The 3,266 cases in 2023 were triple that of 2018. Gay and bisexual men account for nearly half of cases and women for about a quarter of them.

Dunnington stressed the importance of women and their partners understanding the risks of congenital syphilis and the importance of being tested. That can take courage, she says.

“There’s a lot of stigma around sexually transmitted infections, and so it’s about not being afraid to seek out testing,” she said. “As health care providers, we’re here to help support them.”