International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases
October 19, 2026 · via Europe PMC
Clinical and serological outcomes for successive syphilis episodes in people with HIV.
Casado JL, Moreno A, Rodríguez-Domínguez M, Romero-Hernández B, Izuzquiza I, Vizcarra P, Luna L, Vallejo A.
AI summary — for doctors, generated from the abstract only
In people with HIV, serological response to syphilis treatment was similar across repeated episodes, but secondary-stage presentation became less frequent and serofast status more common.
What was studied
Prospective cohort of 183 adults with HIV and 362 syphilis episodes (2016-2024), comparing presentation and serological response across first, second and later episodes.
Key findings
- Secondary stage was less frequent in successive episodes (21%, 11%, 13%; p=0.048)
- 12-month serological response was similar (75%, 83%, 78%)
- Serofast status rose across episodes (33%, 62%, 64%)
- Shorter inter-episode interval correlated with faster subsequent response (rho=0.226)
Clinical relevance
Clinicians managing HIV and syphilis should expect more serofast results with repeat infections without assuming treatment failure.
Limitations
Observational single cohort; the abstract is partly cut off, and findings are only compatible with, not proof of, partial immunity.
Do not assume treatment failure or neurosyphilis solely because RPR stays serofast after repeat syphilis in PWH.
This is an AI-generated summary of the published abstract, not a clinical recommendation. It may not reflect the full text or subsequent updates — verify against the original source before acting on it.
Abstract
Background
Syphilis incidence continues to rise globally among people with HIV (PWH), in whom repeated episodes are common and contribute to ongoing transmission. Whether prior infections modify clinical presentation, serological response, or treatment outcomes remains poorly understood. Partial immunity against Treponema pallidum has been proposed, but its clinical relevance across successive episodes has not been evaluated in a prospective cohort. The objective was to compare clinical presentation, time to serological response, serofast status, and seroreversion across successive syphilis episodes in PWH.
Methods
Prospective cohort study of adult PWH diagnosed with a confirmed first syphilis episode and subsequent syphilis episodes between January 2016 and December 2024. The primary endpoint was serological response, defined as a ≥4-fold RPR (rapid plasma reagin) titer decline or seroreversion before or at 12 months after treatment; episodes with reinfection before 12 months were excluded. Successive episodes were defined as confirmed reinfections, a ≥4-fold RPR rise after serological response, and they were compared using survival and regression models.
Results
We evaluated 362 syphilis episodes in 183 PWH over 1,445 person-years of follow up. In repeated episodes (1st vs 2nd vs ≥ 3), a secondary syphilis stage was less frequent (21% vs 11% vs 13%: p=0.048). Serological response at 12 months was similar in repeated episodes (75%, 83%, and 78%), associated with a high RPR titer and higher nadir CD4+ count (RR 1.004; p=0.047). A shorter inter-episode interval correlated with a faster serological response in the following episode (rho=0.226; p=0.029). Serofast status was more frequent in successive episodes than in the first (33%, 62%, and 64%; p<0.001), and inversely less for seroreversion (57%, 32%, and 20%; p<0.001), after adjusting by time of follow up. A final diagnosis of neurosyphilis was made in 4%, 1%, and no cases, respectively.
Conclusions
Non-treponemal test titers and serological response rates at 12 months are consistent across successive syphilis episodes in PWH. An attenuation of secondary-stage presentation, a shorter inter-episode interval associated with a faster subsequent serological response, and a progressive rise in serofast status not attributable to treatment failure or neurosyphilis are findings compatible with, though not direct evidence of, partial immune memory.
DOI
10.1016/j.ijid.2026.109201
PMID
42896730
Research metadata (titles, abstracts, authors, publication dates) is sourced from Europe PMC, which aggregates content from PubMed/MEDLINE, PubMed Central, and other providers under the U.S. National Library of Medicine (NLM/NCBI). NLM does not claim copyright on abstracts; the original journal publishers or authors may hold rights to the full articles. AI-generated summaries are derived only from the abstract, never the full text, and are always labeled as AI-generated.
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