File this under ‘things you likely didn’t expect to hear in 2023’: Syphilis is raging and an expected penicillin shortage next year is likely to exacerbate the epidemic.

Biopharmaceutical company Pfizer says demand is high due to the rising rate of syphilis infections. That’s led infectious disease experts to warn that a shortage could make things worse.

The company says the high demand is specifically for Bicillin [BYE-sill-in] L-A, a type of long-acting injectable penicillin that’s particularly effective against the sexually transmitted infection.

Syphilis infections have been rising in the U.S. since 2000. The Centers for Disease Control and Prevention reported more than 176,000 cases in 2021, up 75% from 2017.

Left untreated, syphilis causes sores, a rash and damage to internal organs, the nervous system, eyes and ears. It can be deadly.

Bicillin is important for pregnant women because it prevents transmission to the fetus.

To stretch the supply, the CDC encourages doctors to prescribe Bicillin to pregnant patients and exposed infants. Others would be prescribed doxycycline [daak-suh-sai-kleen] for two to four weeks.

Syphilis has been around for centuries, but it wasn’t until 1943 that penicillin was used, a far more effective treatment than the mercury or plant-based potions of the past.

Experts say if you’re sexually active or pregnant, being screened is a no-brainer. Transmission happens through contact with syphilitic sores. While condoms aren’t 100% effective, they do reduce the risk.

And remember, we’ve been here before: Syphilis spiked in the early 1990s before intense public health focus helped rein it in.