First at-home syphilis test approved by FDA amid nationwide syphilis surge

At-home syphilis tests could improve access and help fight epidemics

By Saima S. Iqbal

On August 16, the U.S. Food and Drug Administration authorized the sale of the first over-the-counter home test kits for syphilis, part of an effort to halt a nationwide surge in sexually transmitted infections (STIs).

The new test, which delivers results in under 15 minutes, draws blood from a fingerprick and scans it for immune molecules called antibodies that bind to the bacteria that causes syphilis. A positive result requires follow-up by a medical professional who can confirm ongoing infection and provide effective antibiotic treatment. Manufacturer NOWDiagnostics says the product will be available in pharmacies and retail stores later this year.

Other types of rapid syphilis tests can only be administered by health care professionals or certain community groups. But stigma often makes people, and the health care providers who work with them, hesitant to bring up concerns about their sexual health. Similar to the at-home tests for gonorrhea and chlamydia approved late last year, this new syphilis test allows people to get tested in the privacy of their own home.

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“This is really groundbreaking,” says Jeffrey Klausner, former director of the San Francisco Public Health Department’s Sexually Transmitted Disease Prevention and Control Service and an epidemiologist at the Keck School of Medicine of the University of Southern California.

Over the past decade, the United States has seen a surge in cases of most sexually transmitted diseases, including syphilis. From 2018 to 2022 alone, the number of syphilis cases in the United States increased by nearly 80%, exceeding 207,000 cases, a 70-year high. The disease is increasingly common among pregnant women, who can also transmit it through the bloodstream or to a fetus in the womb during vaginal birth. According to the U.S. Centers for Disease Control, 280 out of every 100,000 births will be infected with syphilis in 2022, and 3,700 babies will be born with syphilis.

Some untreated infected people suffer severe damage to the heart, brain, and other major organs. Syphilis infection during pregnancy often causes miscarriage and infant death.

Public health experts say the spike in infection rates reflects widespread difficulties in accessing health care. “Syphilis is like the canary in the coal mine,” explains Barbara van der Pol, an epidemiologist at the University of Alabama at Birmingham. “Whenever the public health infrastructure is dysfunctional, syphilis is going to increase.”

Funding for sexual health clinics in the US has declined over the past two decades, when adjusted for inflation, leading to many organisations that raise awareness and support testing for STIs ceasing operations, according to van der Pol and Klausner.

Syphilis can be difficult to spot for the untrained eye. Soon after infection, genital sores appear, and a few weeks later, a full-body rash and fever often appear. But the sores are often painless and may be hidden inside the vagina or anus. Doctors can also mistake the symptoms of the second wave of syphilis for those of a common viral infection. After a year, the bacteria go dormant in the body, but remain infectious to some extent, and people can sporadically develop serious health complications. According to Arlene Seña Soberano, a public health researcher at the University of North Carolina at Chapel Hill, these complications are increasingly occurring in previously healthy adults weeks or months after infection.

Those at increased risk of infection include those who have unprotected sex or multiple sexual partners, men who have sex with men, people with HIV or other immunosuppressants, and people who inject drugs. The CDC also recommends annual testing for all sexually active people ages 15-44 in areas where the syphilis incidence rate in women in that age group is greater than 0.0046%, regardless of their individual sexual habits. All pregnant women are recommended to be tested at their first prenatal visit.

To more effectively stop the spread, van der Pol says the US needs to foster a culture of regular STI testing. “Once people get tested at least once a year, or whenever they have an underlying concern — once you really normalize it — then we’ll start to see an impact,” she adds.

In Klausner’s view, stigma prevents communities from rallying together to pressure government for more action. “The reality of a democratic society is that resources go to the people who are the loudest,” he says. Earlier this year, the Department of Health and Human Services created a national task force to respond to the syphilis epidemic. Klausner thinks activists could pressure the federal government to make rapid tests like the one recently approved available for free through local health departments and community organizations.

The new test, with an estimated list price of $29.98, may not serve some of the most vulnerable, such as those who are unhoused or have substance use disorders. Sexual health advocates may encourage governments to manufacture penicillin, a frontline treatment that began in June 2023 due to disruptions in the global supply chain and was only partially alleviated a few months ago. (Alternative treatments exist, but they are cumbersome to use and not safe for pregnant women.)

“When I was public health commissioner for San Francisco, it was clear that with political will and enough resources, we could get this type of infection under control,” Klausner said.