Syphilis is not only still around, it’s surging. The United States reported over 190,000 total syphilis cases in 2024, and the World Health Organization estimates 8 million adults worldwide acquired the infection in 2022 alone. After decades of decline that led many people to think of it as a relic of the past, syphilis has been climbing steadily since the mid-2010s and is now considered a public health crisis in the U.S.
How Big the Problem Is Right Now
The numbers tell a striking story. In 2024, the CDC recorded 190,242 total syphilis cases across the country. That’s actually a 9% drop from 2023, and cases of primary and secondary syphilis (the earliest, most infectious stages) fell 22% year over year. But those declines come after years of steep increases, so the overall level remains far higher than it was a decade ago.
The most alarming trend involves newborns. Congenital syphilis, which occurs when a pregnant person passes the infection to their baby, has risen for 12 consecutive years. Nearly 4,000 cases were reported in 2024, up roughly 700% since 2015, when just 495 cases were recorded. Congenital syphilis can cause stillbirth, bone deformities, and organ damage in infants, making it one of the most preventable yet devastating outcomes of the epidemic.
Why Syphilis Made a Comeback
No single factor explains the resurgence. Researchers point to a combination of forces working together. Cuts to public health budgets have left fewer workers available to track infections, notify sexual partners, and connect people with treatment. STI clinics across the country have closed or reduced hours over the past two decades, shrinking the safety net that once kept syphilis rates low.
For congenital syphilis specifically, delayed prenatal care plays a major role. More than a third of women diagnosed with syphilis during pregnancy didn’t have a prenatal visit in the first trimester, meaning they missed the window for early screening and treatment. Substance use, incarceration, and lack of health insurance all make it harder for pregnant people to access consistent care, and those factors overlap heavily with the communities seeing the highest rates.
Who Is Most Affected
Syphilis doesn’t hit every group equally. Maternal syphilis rates in 2024 were highest among American Indian and Alaska Native mothers (2,145 per 100,000 births), followed by Native Hawaiian or Other Pacific Islander mothers (1,005 per 100,000) and Black mothers (888 per 100,000). White mothers had a rate of 188 per 100,000. Every racial and ethnic group saw increases from 2022 to 2024, but the disparities reflect longstanding gaps in healthcare access rather than differences in sexual behavior.
Among pregnant people, the youngest age groups have the highest rates: 514 per 100,000 births for those aged 20 to 24, and 474 per 100,000 for those under 20. But rates rose across all age groups, including women over 40.
What Syphilis Looks and Feels Like
One reason syphilis spreads so effectively is that it’s easy to miss. The infection progresses through distinct stages, and each one can be subtle enough to ignore.
In the primary stage, a sore appears at the spot where the bacteria entered your body, typically on or around the genitals, anus, rectum, or mouth. The sore is usually firm, round, and painless, which is why many people never notice it. It lasts three to six weeks and heals on its own whether or not you get treated. That healing can create a false sense that nothing is wrong.
The secondary stage brings a rash that can appear on your palms, the soles of your feet, or other parts of your body. It’s often rough and reddish-brown but sometimes so faint you won’t see it, and it typically doesn’t itch. You might also experience fever, swollen lymph nodes, sore throat, patchy hair loss, headaches, weight loss, or muscle aches. These symptoms also resolve on their own, which again tricks people into thinking they’re fine.
After the secondary stage, the infection enters a latent period with no visible signs or symptoms at all. This can last years. If left untreated, some people eventually develop tertiary syphilis 10 to 30 years after the initial infection. At that point, the bacteria can damage the heart, blood vessels, brain, and nervous system, and the results can be fatal. Not everyone with untreated syphilis reaches this stage, but the consequences for those who do are severe.
Complications That Can Strike at Any Stage
Syphilis can also spread to the brain, eyes, or ears at any point during the infection, not just in the late stages. When it reaches the brain, it can cause severe headaches, muscle weakness, confusion, personality changes, and dementia. When it affects the eyes, it can cause pain, redness, vision changes, or blindness. In the ears, it can lead to hearing loss, ringing or buzzing sounds, and vertigo. These complications are uncommon but serious, and they’re another reason early detection matters.
How Syphilis Is Detected
Syphilis is diagnosed through blood tests. Most screening today uses what’s called a reverse sequence approach: a lab first runs a test that detects antibodies your body produces specifically in response to the syphilis bacterium. If that’s positive, a second test measures a different type of antibody that indicates active infection. If the two results don’t match, a third test helps sort out whether you have a current infection, a past treated infection, or a false positive.
The process is straightforward, but you have to be tested in the first place. Because syphilis symptoms are easy to overlook or mistake for something else, routine screening is the most reliable way to catch it. If you’re sexually active with new or multiple partners, testing is the only way to know for sure.
Treatment Works, but Supply Is Strained
Syphilis is curable with penicillin, which has been the standard treatment for decades. A single injection can treat early-stage syphilis, and the cure rate is excellent when the infection is caught before it causes organ damage.
The problem right now is supply. The only FDA-approved injectable penicillin formulation used to treat syphilis in the U.S. has been in limited supply, and the manufacturer doesn’t expect full recovery of the supply until late 2027. The FDA has allowed temporary importation of an alternative formulation to help fill the gap, but the CDC has recommended that available doses be prioritized for pregnant patients, since penicillin is the only treatment option for pregnant people and newborns with congenital syphilis. Alternative antibiotics exist for non-pregnant adults, but the shortage adds another obstacle to controlling the epidemic.
The Bottom Line on Syphilis in 2025
Syphilis never disappeared. It reached historic lows in the U.S. around 2000, leading to optimism that elimination was possible, but cases have climbed relentlessly since then. The recent year-over-year declines in new adult cases are a cautiously positive sign, but congenital syphilis is still rising, the medication supply is constrained, and public health infrastructure continues to face cuts. Syphilis is treatable and preventable, but only if people know to look for it and have access to care when they need it.