Kinetics of RPR Decline in Pregnant Persons Treated for Syphilis in Pregnancy and Their Infants
Bibliographic record
Abstract
Congenital syphilis is a re-emerging infectious threat in areas of North America. The purpose of this study was to quantitatively describe the rate of decline of nontreponemal (rapid plasma reagin, RPR) titers in pregnant persons with syphilis and their infants. In a retrospective review, we included 120 pregnant persons with 563 reactive RPR measurements (median 5, range 2 to 11 per person) and 35 infants with 81 RPR measurements (median 2, range 2 to 6 per infant). First-order decay, second-order decay, and a mathematical model representing functional FcRn-mediated antibody recycling were fitted to individual patient RPR trajectories. The RPR titers decreased with a median half-life of 39 days (IQR 28-59) and 27 days (IQR 17-41) in birthing parents and infants, respectively. The half-life varied with the initial RPR titer, suggesting that the kinetics of RPR decline was not first-order. A mathematical model accounting for saturable antibody recycling explained the longevity of RPR reactivity, predicted the observed non-linear kinetics, and fit the empiric data well. In summary, RPR titers decline with a half-life of roughly one month; however, the elimination does not follow first-order kinetics. Saturable antibody recycling may explain the prolonged and non-linear elimination of nontreponemal antibodies.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.009 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".