Cases of newborn syphilis in the United States have risen for the past 12 years, despite a slowdown in the past year or two, according to new data from the Centers for Disease Control and Prevention (CDC). 

Although the increase of 2% reported from 2023 to 2024 was modest compared with previous years, cases of newborn syphilis increased by nearly 700% from the 475 cases reported in 2015 to the 3941 cases reported in 2024, according to the CDC. 

Overall, the rate of sexually transmitted infections (STIs) in the United States remains high, according to the CDC. More than 2.2 million cases of any type of STI were reported in 2024, but this represents a 9% decrease from 2023, continuing a 3-year trend of decreasing cases. 

Notably, primary and secondary syphilis rates dropped for the second consecutive year and decreased by 22% from 2023 in adults, according to the CDC. 

The declines probably reflect public health efforts, including increased awareness of STIs and greater use of prevention measures such as self-testing, but rates remain high and more prevention efforts are needed, according to the CDC. 

Data Spotlight Need for Early Intervention 

Congenital syphilis, transmitted during pregnancy, affects the skin, eyes, heart, liver, and brain in infants, and can lead to stillbirth, infant death, and significant disability, said Jennifer Qin, MD, a maternal-fetal medicine fellow at the University of Washington, Seattle, in an interview. Congenital syphilis can affect children for the rest of their lives, but adverse outcomes are preventable with treatment during pregnancy, so early identification of women at risk is important, said Qin, who was not involved in the study. 

“Our clinical guidelines recommend screening for syphilis for all pregnant individuals at least twice in pregnancy: once in the first trimester, and once in the late second or third trimester,” Qin told Medscape Medical News. “However, pregnant patients with syphilis are more likely to receive inadequate care in pregnancy and thus may not receive recommended routine screening,” she said. “Unsurprisingly, most cases of congenital syphilis occur in pregnancies in which timely testing is not performed, or adequate treatment is not received,” Qin added. 

Looking ahead, alternatives are needed to reach pregnant individuals who do not receive routine prenatal care, said Qin. Strategies such as universal testing in emergency departments and substance use treatment centers might help identify more pregnant individuals with syphilis who otherwise wouldn't receive testing, she said. “We also need public health programs to help link those who test positive to treatment,” Qin added. 

The report was supported by the Centers for Disease Control and Prevention. 

Qin had no financial conflicts to disclose.