Sexually transmitted diseases
July 1, 2026 · via Europe PMC
Unknown Duration or Late Syphilis Cases with High Titers-North Carolina, 2015 and 2023.
Gore DJ, Jackson DA, Torrone E, Samoff E, Mobley V, Cope AB.
AI summary — for doctors, generated from the abstract only
In North Carolina, unknown-duration or late syphilis cases quadrupled between 2015 and 2023, with rising high-titre proportions in women and heterosexual men suggesting some are misclassified early infections.
What was studied
Surveillance analysis of UDLS cases reported in North Carolina in 2015 and 2023, comparing proportions with RPR titres ≥1:32.
Key findings
- UDLS cases rose from 628 to 2,498
- Overall high-titre proportion stable (51.3% vs 50.2%)
- High-titre proportion increased in women (29.1% to 46.1%), pregnant women (30.4% to 43.2%), MSW (45.0% to 57.4%) and recently incarcerated (41.7% to 52.9%)
- Decreased among MSM and men with HIV
Clinical relevance
This suggests clinicians should carefully stage syphilis in women and heterosexual men, as high-titre 'late' cases may be early infections relevant to partner notification; data are from one state.
Who should care
Limitations
Single jurisdiction surveillance data; titre is an indirect proxy for infection stage.
Many 'late' syphilis cases in women and heterosexual men may actually be early infections.
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
While recent national increases in unknown duration or late syphilis (UDLS) have outpaced diagnoses of earlier stages of syphilis, the causes and contributors remain unknown. We evaluated changes in the proportion of UDLS cases with high nontreponemal test titers in one jurisdiction to identify if UDLS cases, which often have lower titers compared with early syphilis cases, might increasingly be early syphilitic infections.
Methods
We identified UDLS cases with high titers (defined as rapid plasma reagin titers ≥1:32) reported to North Carolina during the years 2015 and 2023. We evaluated changes in case counts and in the proportion of UDLS cases with high titers overall, by demographics, clinical factors, and incarceration history.
Results
When comparing years 2015 and 2023, UDLS case counts increased (628 vs 2498). The proportion of cases with high titers remained relatively stable between both years (51.3% vs 50.2%), but increased among women (29.1% vs 46.1%), women pregnant at the time of syphilis diagnosis (30.4% vs 43.2%), men who have sex with women only (45.0% vs 57.4%), and people who were recently incarcerated (41.7% vs 52.9%). The proportion of cases with high titers decreased among men who have sex with men (66.4% vs 58.1%), and men with human immunodeficiency virus (68.0% vs 55.4%).
Conclusions
The proportion of cases with high titers increased among women, men who have sex with women only, and people who were recently incarcerated, suggesting that an increasing proportion of UDLS cases in these populations might be early syphilitic infections. Future initiatives could identify methods of improving case staging to facilitate syphilis prevention and control.
DOI
10.1097/olq.0000000000002379
PMID
42384893
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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