Syphilis Resurgence: Testing Trends, Challenges, and Strategies for Control

After many years of the number of cases declining, syphilis has increased exponentially in the last 10 years in Europe, Australia, and the United States. The CDC recently announced that more than 2.5 million cases of sexually transmitted infections (STIs) were reported in 2022 in the US. In 2018, 113,739 cases of syphilis were reported, compared with 203,500 cases in 2022.

To learn more about what infection control and prevention personnel should know about how testing can help detect and control this disease, Infection Control Today^® (ICT^®) spoke with Deborah Sesok-Pizzini, MD, chief medical officer and global head of quality for Labcorp.

ICT: Can you provide an overview of how the volume of syphilis testing has evolved over the past decade and what trends or patterns have emerged in terms of testing frequency and positivity rates?

Deborah Sesok-Pizzini, MD: Syphilis is a complex systemic illness primarily transmitted by sexual contact or by passage through the placenta in congenital syphilis. Congenital syphilis was nearly eliminated at the turn of this century but jumped 755% over the last decade, according to a recent report from the CDC.

In most of those cases, patients were not tested during pregnancy, and many who tested positive for syphilis did not receive treatment. About 37% of the infected pregnant people did not receive prenatal care, according to the CDC.

Over the past 10 years, Labcorp has seen syphilis testing more than double. In 2012, clinicians ordered 2.36 million syphilis tests, and in 2022, testing increased to 5.5 million. As 2023 comes to an end, we are expecting volumes to continue to increase in 2024.

ICT: Syphilis has seen a resurgence in recent years. How does syphilis testing play a crucial role in detecting and controlling this STI, and what strategies can health care providers and communities employ to curb its spread?

DS-P: Syphilis was nearly eradicated at the turn of this century, so its resurgence should ring alarm bells for health care providers and the public at large. Despite the rapid increase in infections over the last 10 years, this disease is both preventable and curable. Unfortunately, many people who have contracted syphilis may be asymptomatic and, therefore, may not get tested or seek treatment, thus unknowingly contributing to its spread.

Testing is critical to identifying syphilis and other STIs to provide early treatment and prevent transmission. In fact, the CDC reports that in 2022, timely testing and treatment during pregnancy could have prevented about 90% of congenital syphilis cases in newborns.

Health care providers and community leaders play an important role in preventing the spread of diseases such as syphilis by recognizing the need for enhanced screening and by providing educational information about available testing and treatment options.

ICT: Can you elaborate on the various syphilis testing methods available today, and how have technological advancements impacted the accuracy and accessibility of these tests?

DS-P: Labcorp offers both the traditional syphilis algorithm (RPR with reflex to treponemal antibodies) and the reverse syphilis algorithm (treponemal antibodies with reflex to RPR):

The choice of algorithm is based on the prevalence of syphilis in the population being served and provider preference. Each algorithm has advantages and disadvantages and is equally recommended by the CDC. The traditional algorithm may be less sensitive in detecting early or late latent syphilis, while the reverse algorithm may have a higher false positive rate in low-prevalence populations. Providers can order either of these profiles to support the screening and diagnosis of syphilis infections, which provide results in 1-4 days.

Both profiles align with the CDC’s guidance to use a combination of both treponemal and nontreponemal antibody tests to screen for and diagnose syphilis. Syphilis testing is also part of several comprehensive profiles Labcorp offers, including STI profiles and pregnancy profiles, along with hepatitis B and C and HIV.

ICT: In what ways does early detection through syphilis testing contribute to both individual and community-level public health outcomes, particularly in preventing the spread of syphilis and other STIs?

DS-P: For individuals, early detection of syphilis and other common STIs is a key element to achieve improved health outcomes. It facilitates treatment of the infection at its early stages and allows the infected patient to identify and notify individuals who may have been exposed.

Underscoring this point, the CDC found that lack of testing or lack of timely testing accounted for 56% of cases of congenital syphilis in the West, 50% in the Northeast, and 40% in the Midwest region. Through our National Office of Quality, we report syphilis testing at the state level.

At the community level, treating individual cases early can limit the transmission rate. Early detection may also support contact tracing efforts that play an important role in preventing the spread of syphilis and other STIs.

Effective prevention and detection of congenital syphilis depends on identifying syphilis among pregnant women and, therefore, on the routine serologic screening of pregnant women. The CDC recommends screening during the first prenatal visit, at 28 weeks gestation, and at delivery for high-risk patients.

ICT: Are there any specific initiatives or partnerships Labcorp has undertaken to raise awareness about syphilis testing and promote its importance in maintaining community safety?

DS-P: Labcorp realizes the value of partnerships across the healthcare industry and seeks to offer vital information to help providers make confident health decisions for their patients. Labcorp offers various educational resources for providers, like patient screening checklists, CDC testing guidelines, treatment recommendations, and other resources on its website.

Through our Labcorp Venture Fund, we invest in innovative start-up companies, like NOWDiagnostics (NOWDx), a developer of over-the-counter and point-of-care diagnostics tests and first-in-class technology and platforms, which announced in January 2024 that it had submitted a De Novo Classification Request to the US Food and Drug Administration for the company's First to Know at-home syphilis test.

Ovia Health by Labcorp also provides education about sexually transmitted infections as part of their core in-app programming. Pregnant Ovia members are also prompted to undergo screenings for STIs according to the CDC recommendations as part of their Personalized Health Pathway in the Ovia+ solution.

ICT: Looking to the future, what innovations or developments in syphilis testing can we anticipate, and how might these advancements further enhance our ability to combat the spread of syphilis and other STIs?

DS-P: STIs are not usually something people think about or want to talk about; however, most are treatable and/or curable, especially if detected early. Labcorp encourages individuals to prioritize their health by regularly visiting health providers and performing routine health screenings.

While we continue to work with partners such as NowDx on innovative, more convenient, and accessible ways to screen for syphilis, Labcorp also offers STI testing through Labcorp OnDemand. A simple urine test that is purchased online—without the need for a doctor’s visit—can screen for gonorrhea, chlamydia, and trichomoniasis all in one.