Slowing Resurgent Syphilis in People With HIV

Preventing Syphilis: Easy and Hard

Syphilis prevention campaigns have featured a giant, roving penis and a walking, raspberry-like syphilis sore.⁶ These eye-grabbing ploys may raise public awareness for a few minutes, but slowing the syphilis resurgence probably demands sterner tactics. Preventing syphilis remains frustrating because it is both simple and Sisyphean. It's simple because everyone knows what's required: better public understanding of how syphilis spreads, safer sexual gymnastics, more zealous syphilis and HIV screening, and earlier diagnosis and treatment of both STIs. It's Sisyphean because progress on all these fronts comes slowly.

Even though T pallidum can be transmitted orally, condoms do appear to mitigate transmission risk. Circumcision does not. A systematic review of studies addressing condom use and syphilis risk did more to highlight how poorly designed such studies have been than to suggest a conclusion.⁸⁸ The two studies that examined both incident syphilis infection and consistent condom use both found that regular rubber wearing did lower syphilis risk, and in one study the association was statistically significant. None of the 12 studies evaluated assessed correct condom use or documented exposure to a sex partner with syphilis.

Researchers who prospectively study a cohort of HIV-positive and negative people in Rakai, Uganda famously demonstrated (with two other groups) that circumcision significantly lowers the risk of HIV acquisition by heterosexual men. Continuing research showed that circumcision also significantly cut HSV-2 infection incidence and HPV infection prevalence.⁸⁹ But that analysis turned up no evidence that circumcision helps shield heterosexual men from syphilis.

A Cochrane Database review of 8 studies involving 34,999 MSM confirmed that circumcision does not stop syphilis in this population.⁹⁰

Scientists have sequenced the entire T pallidum genome, a key step in identifying surface molecules and thus in designing a vaccine.⁶ Warning that development of a protective syphilis vaccine remains "formidable," Ho and Lukehart note that studies are under way to test the ability of a "cocktail of conserved regions on T pallidum antigens" that might confer immunity in a rabbit model.³⁹

In the meantime, notifying sex partners of people with recently diagnosed syphilis -- and perhaps treating them presumptively -- may slow the spread of this sinuous pathogen. HRSA HIV guidelines advise that sex partners of anyone diagnosed with primary, secondary, or early latent syphilis in the past 90 days "should be treated presumptively, as they may be infected with syphilis even if they are seronegative."⁴⁵ Sex partners exposed more than 90 days after such a diagnosis should be treated presumptively "if serologic test results are not available immediately and their follow-up is in doubt."⁴⁵ HRSA adds that some specialists recommend presumptive treatment for sex partners of people diagnosed with primary syphilis in the past 3 months, secondary syphilis in the past 6 months, or early latent syphilis in the past year.

From the first days of the US syphilis resurgence, Internet partnering has helped spread T pallidum.¹⁹ Zetola and Klauser¹² believe public health officials and providers should not overlook the potential of this fluid medium to notify partners of syphilis patients, promote awareness of this tenacious STI, and offer testing to people who may need it.^20,91-93