Repeat syphilis episodes in MSM highlight need for increased awareness, novel strategies
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Sexual risk behaviors appear to be a large driver of novel syphilis infections among men who have sex with men, or MSM, who are HIV-positive and have had prior episodes of syphilis infection. Experts say that access to sexual encounters and increased testing – and, therefore, greater awareness of those who are infected – may also be contributing to increases in repeat episodes.
“Syphilis is re-emerging globally in general and HIV-infected populations and repeated syphilis episodes may play a central role in syphilis transmission among core groups,” Manuel Battegay, MD, professor in the Division of Infectious Diseases and Hospital Epidemiology at University Hospital Basel, told Healio. “Besides sexual behavioral factors, before this study, we knew little about determinants of repeated syphilis episodes in HIV-infected individuals — including the potential impact of preceding syphilis episodes on subsequent syphilis risk.”
To learn more, Battegay and colleagues performed a prospective analysis of patients in the Swiss HIV Cohort Study, examining data from 2,513 HIV-infected MSM who initially had a negative syphilis test, with the goal of identifying first and repeated syphilis episodes and determining the associated risk factors.
There was no indication of decreased syphilis risk with repeated syphilis episodes, according to the researchers. In univariable and multivariable analyses, the number of prior syphilis episodes (adjusted HR per one-episode increase = 1.15; 95% CI, 1.01-1.31), having occasional sexual partners with or without condomless anal sex (aHR = 4.99; 95% CI, 4.08-6.11 and aHR = 2.54; 95% CI, 2.10-3.07) and currently being on antiretroviral therapy (aHR = 1.62; 95% CI, 1.21-2.16) were associated with incident syphilis.
“The most important fact is that repeated episodes of syphilis are not rare and that repeated testing and screening, also without symptoms, [are] essential to discover new episodes,” Jan A. Roth, MD, of the Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel at the University of Basel, told Healio. “It is crucial to recommend frequent testing for syphilis in MSM [and to] implement this knowledge into daily practice. This is done in the Swiss HIV Cohort Study.”
In the United States, Jason Halperin, MD, an infectious diseases physician at CrescentCare in New Orleans, has noticed a similar epidemic of syphilis, noting that patients come in repeatedly for testing and treatment. He says the drivers of this national and international epidemic need to be teased out to end it.
One primary driver of the increased rates of repeated syphilis cases is more frequent testing among users of pre-exposure prophylaxis (PrEP) and MSM, Halperin noted.
“We have patients who are coming in and are likely being tested more frequently than ever as we recognize this epidemic,” he told Healio. ”We may be capturing infections that were always there, but we’re actually seeing them now, especially in our PrEP population, who we used to see maybe once per year. We are now these patients seeing multiple times per year.”
He added that greater accessibility to sexual experiences, through platforms like social media and dating apps, may also be driving the epidemic, noting that these make brief sexual encounters easier to access than ever before.
Regardless, Halperin says that stigma needs to be addressed and overcome in order to get ahead of the issue. Patient populations that are battling stigma are not engaging with the medical community and in care, which leads to higher odds of transmission.
“We have to think through how we can make coming into the health system as welcoming as possible and how we can become more proximate to the populations we serve,” Halperin told Healio. “We must get out of our clinic comfort zone by embracing mobile clinics or community partnerships, for example, and we have to recognize this epidemic and think more creatively to overcome it.” – by Caitlyn Stulpin
Disclosures: Battegay, Halperin and Roth report no relevant financial disclosures.
Perspective
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Paul A Volberding, MD
HIV, as we all know, is a sexually transmitted infection, so it’s not surprising that HIV-infected MSM are at risk for other STIs, including syphilis. Interest in these dual infections has increased with rising syphilis incidence and with concern that strategies like PrEP and ”undetectable equals untransmittable” may decrease condom use and result in increased syphilis transmission. Although research continues, there is no effective syphilis vaccine, but one question has been whether or not prior syphilis infection confers any partial immunity to repeat infection. This was the main question explored by the current investigation. In the highly organized and productive Swiss HIV Cohort, the researchers identified new syphilis cases in cohort members with or without a prior documented infection, asking whether the incidence was decreased by a prior syphilis diagnosis. In fact, no such relationship was found, suggesting a lack of immunity to the organism triggered by infection. Unsurprisingly, syphilis risk was associated with sex, including condomless anal sex, and it was interestingly higher in those on ART. The results underscore the need to address STI prevention in MSM, perhaps including reminders on the benefits of condom use, even in those on suppressive ART.
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