Researchers from Monash University and Alfred Health’s Melbourne Sexual Health Centre are calling for increased use of rapid diagnostic tests (RDTs) for syphilis, particularly among pregnant women and men who have sex with men (MSM). The economic analysis reveals that these tests are not only cost-effective but also crucial for improving health outcomes, especially in women of reproductive age.
The push for RDTs comes at a time when syphilis infections are surging both globally and domestically. In August, Chief Medical Officer Professor Michael Kidd declared syphilis a Communicable Disease Incident of National Significance. This declaration follows a troubling rise in congenital syphilis cases, which have led to numerous newborn deaths in Australia. Survivors often face severe developmental issues, including impaired brain function, hearing, and vision.
Economic and Health Benefits of Rapid Testing
The study, published in The Lancet Infectious Diseases, evaluated three rapid testing algorithms based on the two main types of rapid tests available. Researchers compared their cost-effectiveness, accuracy, and the number of active cases missed, as well as instances of overtreatment. These factors were analyzed with consideration of disease prevalence at a population level.
Ying Zhang, the first author from the Monash University School of Translational Medicine, emphasized the importance of rapid testing. “The first rapid test for syphilis alone was approved in 2020, so this work is filling a knowledge gap about what works best for different groups, and getting the balance right between overtreatment and missing cases, based on the epidemiology,” she said.
“Confirming an active syphilis case can be difficult – especially when we don’t have a patient’s medical history – and tests don’t tell the whole story.”
Testing Strategies for Different Populations
For pregnant women, the study found that the simplest and cheapest test, known as T-RTD, was the most effective. Zhang noted, “T-RTD can’t distinguish between an old infection that no longer needs treatment, and a new active infection. But the impact of missing a syphilis case in pregnancy is so extreme that overtreatment is a lesser evil.”
Conversely, for populations with higher prevalence, such as MSM in urban areas, a modified version of the dual T/NT-RTD test showed better results in terms of cost and health outcomes. This algorithm significantly reduced missed cases by over 90%, according to Zhang. “Urban clinics tend to have better triage and follow-up care, so they can more easily mitigate the impact of overtreatment,” she added.
“You can get syphilis more than once, so we want to avoid overuse of antibiotics, which of course contributes to resistance.”
Implications and Future Steps
Professor Jason Ong, senior author and Director of the Melbourne Sexual Health Centre, highlighted the need for tailored testing approaches. “In pregnancy, a simpler test that may treat a few extra people unnecessarily is better than missing an infection that could harm a baby. But for men at higher risk, using a test that’s more precise helps avoid unnecessary treatment while still finding most cases,” he explained.
Ong emphasized the importance of making these tests widely available, particularly in antenatal care and communities with a high infection burden. “Lab tests are the gold standard in syphilis testing, but time is critical, especially for pregnant women. And in settings where access to labs and healthcare is difficult, rapid tests should be the first-line option.”
The study underscores the urgent need for healthcare systems to adapt and implement rapid testing strategies to curb the rising tide of syphilis infections. As researchers continue to explore the most effective testing algorithms, the focus remains on ensuring timely and accurate diagnosis to prevent further health complications.
Read the research paper: https://doi.org/10.1016/S1473-3099(25)00588-2
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