Why Syphilis Cases in Newborns Are Rising Even as STIs Decline

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The number of babies being born with syphilis in the U.S. kept increasing last year, even as the number of cases of sexually transmitted infections (STIs) in the country dropped, according to new government data.The overall number of reported STI cases fell 9% in 2024 from 2023, the third year in a row that case numbers have declined, provisional data released by the Centers for Disease Control and Prevention (CDC) this week shows. But cases of syphilis in newborns, also known as congenital syphilis, increased for the twelfth straight year. Nearly 4,000 cases were reported in 2024—up almost 700% since 2015, when just under 500 were reported.[time-brightcove not-tgx=”true”]The rise in congenital syphilis cases wasn’t as steep in 2024 as it has been in previous years—just under 2% from 2023. Dr. Bradley Stoner, the director of CDC’s Division of STD Prevention, says that it’s promising that the rate of increase is slowing, but that the rising case numbers are still concerning. Only a couple decades ago, cases of congenital syphilis were nearly eliminated from the U.S. Congenital syphilis is preventable; syphilis can be cured with treatment, and if it’s treated during pregnancy, that can protect the fetus from becoming infected.But if left untreated, syphilis can be passed on to a fetus during pregnancy or delivery. Syphilis can damage organs such as the heart and brain, and can lead to blindness, deafness, and even death. Congenital syphilis can also lead to miscarriage and stillbirth.Stoner says that reductions in STI services at the state and local levels, as well as social and economic conditions such as poverty and lack of health insurance, have likely contributed to rising rates of syphilis, which in turn led to increasing rates of congenital syphilis. Federal funding for STI prevention has seen drastic cuts since the early 2000s. The number of people living in poverty skyrocketed during that period, though it has since declined. And while the percentage of people who are uninsured has fallen since the Affordable Care Act was signed into law in 2010, millions are still uninsured or underinsured. Other complications in accessing quality care could impact people with insurance as well.Elizabeth Finley, interim executive director of the National Coalition of STD Directors, says part of the problem is that pregnant people’s access to health care or preventive syphilis care may vary. For instance, some people may not be able to access prenatal care consistently or at all. And some health care providers may be seeing syphilis cases for the first time in their careers.“You get this perfect storm of people who aren’t getting enough prenatal care to begin with for many, many reasons, and then you see providers who haven’t had to identify or test for syphilis in the past,” Finley says.There have also been intermittent drug shortages that have affected doctors’ ability to quickly treat pregnant people with syphilis, Finley says.She points out that the overall STI rates have gone up over the past decade or so as well.“Overall over the past 10 years, we’ve seen more cases,” Finley says. “Any time there are more STI cases in a community or more cases of any infection—and in this case, syphilis—in a community, you have an increased likelihood that pregnant women will be exposed to it and then that their infants or their fetuses will be exposed to it.”The overall prevalence of STIs in the U.S. is still high, with more than 2.2 million reported cases in 2024—up 13% since 2015, according to the CDC. Finley says that part of the reason for that is because the U.S. has “really divested significantly from prevention efforts.”The CDC noted a few areas of progress in addressing the problem: cases of the two most infectious stages of syphilis, known as primary and secondary syphilis, declined nearly 22% for the second year in a row. Stoner says he is hopeful that congenital syphilis will follow. And cases of gonorrhea and chlamydia continued to fall, too. The agency attributed those declines to the impact of public health initiatives, such as increased awareness about STIs and the use of prevention tools. Those tools include self-tests and the antibiotic doxycycline, which can be taken within 72 hours after sex to help reduce the risk of acquiring syphilis, chlamydia, and gonorrhea.“The data do suggest that we may be turning the corner on STIs,” Stoner says. “But the fact that congenital syphilis is still a major problem tells us that we have to accelerate progress to stop the STI epidemic and its most tragic consequences. These are preventable infections, and greater awareness and greater early intervention, I think, will help us get these infections under better control.”The CDC recommends that people get tested for syphilis three times over the course of their pregnancy. Stoner also encourages people of reproductive age to get tested for syphilis, and to have conversations with their partners about STis.Finley says that, while it’s been encouraging to see public health initiatives try to address this issue, there needs to be a “much more coordinated and intentional effort” to bring various government agencies together to tackle congenital syphilis. She adds that funding for STI prevention efforts have dropped significantly in recent years.“These syphilis cases in pregnant patients don’t happen in a bubble; they happen in a broader context, and right now that broader context is that our overall STI rates are too high,” Finley says. “This really does need to be a part of a broader effort to reduce STIs in the U.S.”