More than 2,000 infants in the U.S. were born with syphilis in 2020, according to recent data presented by researchers with the Centers for Disease Control and Prevention. The preliminary figures represent the highest annual toll of congenital syphilis reported in over 25 years. At least 139 children died from the illness last year.
Syphilis is a bacterial disease caused by Treponema pallidum, typically transmitted through sexual intercourse. In adults, the infection causes initial symptoms like a painless sore near the site of infection, usually the genitals, rectum, or mouth. After a few weeks, the sore heals on its own, but people can then experience skin rashes, swollen lymph nodes, and fever. These symptoms can be so mild that people don’t notice, though. And if the infection goes untreated by antibiotics, it can enter a latent period, where no symptoms occur. Some people with latent syphilis can then experience a third stage years to decades later, in which the disease causes serious organ damage. If syphilis reaches the brain, it can lead to dementia and other irreversible neurological symptoms, even after the infection is finally treated.
Unfortunately, syphilis can be passed from mother to fetus during pregnancy, often with serious complications as a result. The infection raises the risk of miscarriage, stillbirth, congenital defects, and premature delivery. Infants can also die shortly after birth, while some may have no symptoms initially but become sick two to five years later.
In recent years, the U.S. has been experiencing a surge in sexually transmitted infections, including syphilis. And as cases in adults have been growing, so too have cases of congenital syphilis. In a research letter published in the New England Journal of Medicine last week, CDC authors provided the most up-to-date numbers on these infections. So far, there have been 2,022 cases of congenital syphilis reported in 2020, along with 139 related deaths.
These numbers are relatively small, of course, but it’s the highest annual incidence reported in the U.S. since 1994 and continues a trend in rising cases. The spread of congenital syphilis has increased as well, the authors noted. In 2010, cases were reported in 27% of all U.S. counties; by 2020, that number rose to 50%, with cases in 47 states and Washington D.C. And some number of cases will likely be added to the 2020 toll before the reporting period for last year ends next month.
“The resurgence of syphilis among women and its spread to previously unaffected areas underscore the fact that congenital syphilis can occur anywhere,” the authors wrote.
These worrisome trends in STIs started happening before the covid-19 pandemic but don’t seem to have been stopped by it. CDC data has shown that cases did substantially slow down during the early half of the year, when restrictions on movement and in-person contact were strictest. But cases then shot back up toward the end of the year, canceling out the early decline and possibly even leading to yet another yearly increase in STI incidence. This may have happened as a result of restrictions being relaxed over time as well as pandemic-related disruptions that increased our risk in other ways, such as fewer people getting tested for STIs than usual.
This past July, the CDC reported that the incidence of reported syphilis cases in 2020 was only 1% lower than it was in 2019, based on data analyzed up through early December 2020. So it’s possible that the final CDC data will show a net increase in adult syphilis cases last year, just as it now shows a continued rise in congenital syphilis. In 2019, there were 129,813 reported cases of syphilis in total.
Ultimately, the authors say, the most effective way to prevent congenital syphilis is to prevent syphilis in the community generally. But pregnant people should get more attention, especially since congenital syphilis can be still prevented through timely antibiotic treatment up to a month before delivery. The CDC already recommends that every expectant mother be screened for syphilis at their first prenatal visit, while those who have higher risk or who live in higher transmission areas should get added screening at 28 weeks and at delivery.
Bleak as these numbers are, they’re not inevitable. During the height of the HIV/AIDS epidemic in the U.S. during the 80s and early 90s, the authors note, annual cases of congenital HIV were about as high as they are currently for congenital syphilis. But as a result of dedicated efforts in limiting community HIV transmission, improving the screening of mothers, and deploying treatments that can prevent transmission from mother to child, the U.S. saw fewer than 40 cases of congenital HIV in 2019.
“A similar commitment of resources could reduce or eliminate congenital syphilis,” the authors wrote.