Investigating latent syphilis in HIV treatment-experienced Ethiopians and response to therapy

Objectives We investigated people with HIV (PWH) receiving combination antiretroviral therapy (cART) for latent syphilis infection prevalence, risk factors, treatment response, and neurosyphilis. Methods A prospective follow-up study was conducted on PWH and latent syphilis. The cases were randomly assigned to receive either benzathine penicillin G (BPG) or doxycycline (DOXY), and the posttreatment response was evaluated after 12 and 24 months. The traditional algorithm was used for serodiagnosis, and a semi-quantitative rapid plasma reagin (RPR) test monitored disease activity and treatment effectiveness. Results Of the 823 participants, 64.8% were women, and the mean age was 41.7 +/- 10 years. Thirty-one (3.8%) of the participants (22 males and nine females) had latent syphilis. The risk factors were male sex (aOR = 3.14), increasing age (aOR = 1.04 per year), and cART duration (aOR = 1.01 per month). Baseline RPR titers were:.1:4 in 19 (61.3%), between 1:8 and 1:32 in 10 (32.2%), and > 1:32 in 2 (6.4%). None of the seven cerebrospinal fluid analyses supported a neurosyphilis diagnosis. In the 12th month of treatment, 27 (87.1%) had adequate serological responses, three (9.7%) had serological nonresponse, and one (3.2%) had treatment failure. Syphilis treatment was repeated in the last four cases with the alternative drug. In terms of adequate serologic response, both therapies were comparable at the 12th month, p = 0.37. All cases responded to treatment in the 24th month. Conclusion In PWH receiving cART, latent syphilis occurred more in men than women, suggesting an investigation of sexual practices and the impact of antenatal syphilis screening. Syphilis disease activity reduces in the latent stage. Therefore, the routine cerebrospinal fluid analysis contributes little to the diagnosis of asymptomatic neurosyphilis and the treatment success of latent syphilis. DOXY is an alternative to BPG, and cART improves serologic response to latent syphilis treatment.

Automated summary

This study investigated the prevalence, risk factors, treatment response, and neurosyphilis in people with HIV receiving combination antiretroviral therapy (cART) for latent syphilis infection. The results showed a higher prevalence of latent syphilis in men and a reduction in disease activity during the latent stage. Routine cerebrospinal fluid analysis contributed little to the diagnosis of asymptomatic neurosyphilis and the treatment success of latent syphilis. Doxycycline (DOXY) can be used as an alternative to benzathine penicillin G (BPG), and cART can improve serologic response to latent syphilis treatment.