Sexually transmitted disease cases fall, but not syphilis in newborns

Sexually transmitted disease rates for U.S. adults fell last year, but syphilis in newborns continued to rise, according to new government data posted Wednesday.

The Centers for Disease Control and Prevention provisional data for 2024 showed a third consecutive year of fewer gonorrhea cases, and the second year in a row of fewer adult cases of chlamydia and the most infectious forms of syphilis.

But congenital syphilis cases, in which infected moms pass the disease to their babies, aren’t seeing the same improvements. Such infections in infants can lead to deaths or lifelong health problems such as deafness, blindness, and malformed bones.

The number and rate of newborn cases has been rising since 2012, when about 300 were reported, and last year rose to nearly 4,000. The 2024 increases was not as steep as in other years—cases were up by less than 2% from 2023. But health experts say no cases should be happening, and any growth is worrisome.

“The continued rise in congenital syphilis is a distressing indication that we are not doing enough to protect pregnant women and newborns,” said Elizabeth Finley, interim executive director of the National Coalition of STD Directors, in a statement.

About 1.5 million chlamydia cases, 543,000 of gonorrhea, and more than 190,000 of syphilis were diagnosed and reported last year. Each was lower than the year before, and the more than 2.2 million total cases represented a 9% decline from 2023.

Overall decreases in sexually transmitted diseases in recent years have a lot to do with a general decline in young people having new partners, said Dr. Jeffrey Klausner, an infectious diseases researcher at the University of Southern California.

But the drop in adult syphilis cases is generally attributed to the growing use of the antibiotic doxycycline as a morning-after pill, specifically for gay and bisexual men and transgender women who recently had an STD diagnosis. Cases of primary and secondary syphilis, the disease’s most infectious stages, fell 22% last year, the CDC says.

The new data suggests that the improvement in some groups has not yet played out in obstetrics wards. There are several possible factors, but one could be that only 80% of pregnant women are getting screened for syphilis, according to a recent CDC study.

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