For a big chunk of the past two decades, sexual health experts generally thought of syphilis as a disease of greatest concern to gay men and their sexual networks. In 2014, more than 90 percent of US cases were diagnosed in men, the vast majority of whom had sex with other men.
But in 2015, that began to change: Syphilis began ticking upward in heterosexual adults, too — especially among women. By 2021, women accounted for about a quarter of new syphilis cases; the Centers for Disease Control and Prevention recently released data detailing the dramatic rise.
Syphilis causes skin rashes in its early stages and if untreated, in its later stages, can lead to complications ranging from neurologic problems to cardiovascular disease to death (in around 10 percent of cases).
Between 2017 and 2021, infection rates in women rose more than threefold, from two per 100,000 people to seven per 100,000 — a much larger increase than the rise among men, and larger still than the uptick in other sexually transmitted infections (STIs), like chlamydia and gonorrhea. (In absolute numbers, the majority of syphilis infections continue to occur among men who have sex with men, and their infection rates are rising, too. But that increase has been sluggish compared with the meteoric increase among women.)
Syphilis is particularly concerning when it affects women of childbearing age because of the catastrophic effects it can have on pregnancy. Infections in pregnant people can lead to congenital infections in their newborns, placing them at high risk for stillbirth or severe disability. Indeed, congenital syphilis rates have risen precipitously alongside rates in adult women over the past five years.
The reasons for syphilis’s rising rates in women are complex. An unfortunate fact of biology likely plays a part: People with vaginas are more susceptible to STIs than those with penises.
But that anatomical reality, while extremely annoying, isn’t enough to explain why an easily curable STI (with just one dose of antibiotics!) is newly and uncontrollably surging among women. Rising syphilis rates in women — and their babies — signal that multiple societal failsafes have, in fact, failed. This is a big red flag that should provoke us to wonder what’s gone wrong, and to think urgently about fixes.
Here are three theories for how social changes in the US might be contributing to syphilis’s shifting dynamics.
1) Homelessness and substance abuse increase syphilis risk more for women — and those at highest risk are getting less of the care they need.
Among both heterosexual men and women, some of the biggest socioeconomic risk factors for syphilis include drug use — especially opioid, methamphetamine, and heroin use — poverty, homelessness, and transactional sex. Several of these factors have been on the rise in recent years, and they often travel together.
Although these trends affect all genders, it’s among women where they most strongly translate into syphilis risk. Among youth, homelessness raised the risk of syphilis and other STIs far more in girls than in boys. And among people with substance use disorders, women in one study were nearly twice as likely to have transactional sex as men. That led to big negative consequences that fell largely to women: In the same study, people who had transactional sex were three times as likely to have syphilis as those who didn’t.
Meanwhile, the safety-net sexual health services that are supposed to provide preventive care, testing, and treatment for uninsured Americans, including those at highest risk of syphilis, have dwindled. Since 2004, funding for STI prevention has fallen 41 percent, and many counties don’t have a safety-net sexual health clinic at all.
That means many women with the highest vulnerability and the lowest resources — and the men who are most likely to be their sources of infection — are facing bigger barriers than ever to getting tested and treated for syphilis. This is perhaps especially true in rural America. There, the disproportionate impact of the opioid epidemic raises the infection risk for a higher proportion of women — and the disproportionate closure of health facilities more broadly reduces their access to care.
The declines in sexual health care have been going on for decades: Nearly 18,000 women got STI testing and treatment at publicly funded clinics in 2018 — about half as many as in 2010. Simultaneously, more people are getting STI care in emergency rooms, where providers often altogether skip testing for syphilis, Irene Stafford, an OB-GYN and syphilis researcher at the University of Texas Health Science Center at Houston, told me in an interview last fall.
In these settings, providers more often test patients for chlamydia and gonorrhea than for syphilis, she said, as they are more common.
Only about a third of women Stafford sees for syphilis infection complete their treatment, she said, largely because of a mix of socioeconomic challenges and despair. “We have patients who are already mistrusting the government, mistrusting health care, can’t get insured, the health clinics are closed, they’re being trafficked,” she said.
Syphilis’s persistence and growth among women who are already so marginalized shows how poorly equipped the US health care system is for finding and treating disease in the most vulnerable Americans.
2) It’s getting harder to access prenatal care, a key catch-and-treat point for syphilis.
Rising syphilis rates in women may also be linked to another burgeoning crisis: declining access to maternal health care.
Most states require some form of syphilis testing during pregnancy. For that reason, prenatal care is an important tool for catching and treating women’s syphilis infections — and a critical opportunity for preventing these infections from leading to devastating effects in newborns.
But prenatal care is becoming increasingly hard to find. Rural hospitals with birth centers —which usually also offer prenatal care — have been closing at an astonishing rate, and obstetricians have been leaving rural communities for urban centers.
According to the March of Dimes, nearly 7 million women of childbearing age have low or no access to maternity care, and the trend disproportionately affects rural parts of the South and the Plains states.
The lack of access is concerning considering that in 2021, one-fifth of women diagnosed with syphilis were pregnant. How many more cases might be caught if prenatal care access was closer to women in need?
But it’s not just geographic distance that forms a barrier to accessing prenatal care. In 2020, about 11 percent of American women were uninsured — and women without health care coverage are less likely to seek prenatal care.
Additionally, while pregnant women who use drugs are at higher risk for getting infected with syphilis, they face state policies that harshly punish substance use during pregnancy.
“Sometimes people are afraid to seek prenatal care because of the consequences,” said Robert McDonald, a medical epidemiologist who works on syphilis prevention efforts at the CDC, in an interview last fall.
Twenty-four states have laws on the books that consider drug use while pregnant to be child abuse. Several states go even further, allowing women to be jailed or involuntarily committed to rehabilitation if they are found to be using drugs during pregnancy.
The result is that women at highest risk for having syphilis — those with substance use disorders — often avoid the very system that’s intended to protect themselves and their pregnancies.
3) School sex education is failing to give young women practical STI-prevention tools.
In an ideal world, people would learn how to keep themselves from catching syphilis before the opportunity to do so came up. But in many American classrooms, students are getting sex education that simply doesn’t prepare them to avoid STIs.
Sex education in the US is quite the patchwork when it comes to scientific accuracy: Only 17 states require sex ed content to be medically accurate. Meanwhile, 19 states require programs to teach that sex should only happen within marriages, and 29 states require programs to emphasize sexual abstinence.
Programs grounded in religious dogma rather than reality leave young people with more questions than answers about their bodies and about their own sexual health, and make many feel like they’ve done something wrong by being sexually active, or even having sexual thoughts. And their effects are particularly detrimental to young women.
So-called “abstinence-only until marriage” (AOUM) programs reinforce gender stereotypes about passive women and aggressive men. Studies have shown that women who buy into these gender roles are less likely to use condoms, making them more vulnerable to STIs, including syphilis. Studies also showed students who made virginity pledges had higher STI and non-marital pregnancy rates, and were less likely to use condoms and to be tested for STIs.
Stigmatizing sexual activity among teens — whether intentionally or not — also reduces the likelihood that a young woman with an STI will seek care for it. Because syphilis can hang around in the body for years before causing severe symptoms, that means the negative effects of low-quality sex ed in high school can lead to health problems that manifest well into adulthood.
It’s not like there’s no better way: Inclusive, medically accurate sex ed that includes education on healthy relationships and communication has been proven not only to reduce STI rates, but also to lead to lower rates of unwanted pregnancy.
Effective sex ed goes well beyond teaching students the basics of sexual biology, said Michelle Slaybaugh, a former school sex educator who directs social impact and communications at SIECUS, a nonprofit comprehensive sex ed advocacy organization, in an interview last summer.
“Students have to understand what it means to be turned on, what does pleasure feel like,” said Slaybaugh. “Then they can understand, when they are in those moments, how they need to move forward to safely protect themselves and their partners.”
It’s wildly unlikely that such a nuanced brand of sex ed will hit all the US classrooms where it’s needed anytime soon.
Punitive, stigmatizing policies make the situation worse — not better
What so many of the above trends have in common is that they result from policies attempting to incentivize desired behaviors by punishing or stigmatizing undesired ones.
It’s clear in the case of opioids, where the strict punishments for abuse keep people from seeking care.
Similarly, comprehensive sex education could actually reduce young women’s risk for syphilis. But a preference for programs that systematically stigmatize young people’s sexuality means many are deprived of the tools they need to negotiate safe sex.
These policies reduce women’s autonomy, their trust in health care providers, and their ability to get their needs met. Syphilis is just one signal of these punitive approaches’ harms — but it’s one we should heed.