HealthDay News — According to a study published in Sexually Transmitted Infections, men who have sex with men (MSM) receiving antiretroviral therapy (ART) to treat HIV infection may be at increased risk for syphilis.

Based on a review of available evidence, Michael Rekart, MD, from the University of British Columbia’s School of Population and Public Health in Vancouver, Canada, and colleagues concluded that the drugs may boost susceptibility to the bacterium that causes syphilis, although the study did not prove cause-and-effect. 

The finding might explain why new and repeat cases of syphilis in MSM have risen sharply compared to other sexually transmitted infections (STIs) over the past decade, the researchers suggest.

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The authors of an editorial that accompanied the study said the theory is “intriguing” and “warrants careful consideration.” But the editorial also suggested that the increase in syphilis cases among MSM may be due to other factors.

“We are living in an era where ART is being used to effectively treat and prevent HIV infection. To some extent, this seems to have tempered the urgency to control other STIs. As history has shown many times over, that would be a costly mistake,” Susan Tuddenham, MD, and colleagues from the Johns Hopkins University School of Medicine in Baltimore write.

“If further investigations support a role for ART in increasing susceptibility to syphilis, this will provide one more reason why screening, diagnosis and treatment of STIs in MSM must be prioritized,” the editorial authors conclude.


Rekart ML, et al. “A Double-Edged Sword: Does Highly Active Antiretroviral Therapy Contribute To Syphilis Incidence By Impairing Immunity To Treponema Pallidum?” Sexually Transmitted Infections. 2017. doi: 10.1136/sextrans-2016-052870. [Epub ahead of print]

Tuddenham S, Shah M and Ghanem KG. “Syphilis And HIV: Is HAART At The Heart Of This Epidemic?” Sexually Transmitted Infections. 2017. doi: 10.1136/sextrans-2016-052940. [Epub ahead of print]

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