Syphilis and HIV: A Review Maps a Two-Way Infection Partnership

Syphilis and HIV are closely intertwined sexually transmitted infections, and a new review published in AIDS Research and Therapy examines how the two interact in both directions, affecting transmission, clinical manifestations and immunopathogenesis. The article, authored by Luca Pipitò and Antonio Cascio, was published on 17 October 2026 as an open-access review.

According to the review, people living with HIV face a higher risk of acquiring syphilis and of becoming reinfected. The relationship runs the other way as well: syphilis may increase susceptibility to HIV acquisition, and the review notes that syphilis has been associated with transient changes in HIV virological and immunological parameters.

Clinical presentation is a central theme. In people living with HIV, syphilis can appear across a broad spectrum of manifestations, including atypical, severe or multisystemic forms such as neurologic, ocular and malignant presentations. The authors caution, however, that the frequency and clinical significance of these manifestations in routine practice remain uncertain.

Diagnosis poses its own difficulties. The review describes serological diagnosis as potentially challenging because of delayed seroconversion, false-negative results, and slower declines in non-treponemal antibody titers. These factors complicate the interpretation of tests in a population already managing a complex infection profile.

On treatment, penicillin-based therapy remains the mainstay, but the review emphasizes that people living with HIV require careful clinical and serological monitoring. This is because of the potential for inadequate serologic responses and frequent reinfections, particularly in populations at increased risk.

Prevention is also addressed. The authors point to emerging strategies such as post-exposure prophylaxis with doxycycline, which may benefit selected high-risk populations, although they note that evidence remains limited for some groups. The review concludes that understanding the complex interplay between HIV and syphilis is essential to optimizing diagnosis, management, treatment and prevention.

Subject of Research: The interplay between syphilis and HIV in people living with HIV, including diagnosis, treatment and prevention challenges

Article Title: Syphilis in people living with HIV

Article References: Pipitò, L., & Cascio, A. (2026). Syphilis in people living with HIV. AIDS Research and Therapy. https://doi.org/10.1186/s12981-026-00968-0

Image Credits: AI Generated

DOI: 10.1186/s12981-026-00968-0

Keywords: syphilis, HIV, coinfection, sexually transmitted infections, serological diagnosis, penicillin therapy, doxycycline, post-exposure prophylaxis, reinfection, neurosyphilis, review, people