Outbreak of Atypical Pertussis Detected by Polymerase Chain Reaction in Immunized Preschool-Aged Children
Bibliographic record
Abstract
BACKGROUND: From October 2005 to March 2006, a laboratory-confirmed outbreak of pertussis occurred in preschool-aged children (1-4 years) in Toronto, Canada. A case-control study in children was done to identify the risk factors for being positive for Bordetella pertussis by polymerase chain reaction (PCR). METHODS: A case was defined as an individual 0 to 18 years of age who tested positive for B. pertussis by PCR in Toronto from October 2005 to March 2006. Each case was matched to 2 controls (negative for B. pertussis by PCR) by: (1) age, (2) geographic region of testing, and (3) date of testing. RESULTS: One hundred eighty-nine cases and 296 controls were enrolled. Only 42% of cases (vs. 25% controls, P < 0.0001) met a clinical definition of pertussis, 3 cases (4 controls) were hospitalized, and the secondary household attack rate was 8%. One-third of cases were positive for another respiratory pathogen and >90% of cases and controls were up-to-date with pertussis immunization. Children attending school (matched odds ratio [ORm] = 5.2; 95% confidence intervals [CI]: 1.4-19.0), day care (ORm = 2.2; 95% CI: 1.2-4.0), visiting a doctor's office (ORm = 1.6; 95% CI: 1.0-2.5), or exposed to a household member (median age: 4-5 years) with a pertussis-like cough (ORm = 1.9; 95% CI: 1.0-3.6) were significantly more likely to have a positive PCR test for B. pertussis. CONCLUSIONS: The main risk factors for PCR positivity for B. pertussis were school or day care attendance. Atypical symptoms were likely moderated by high immunization rates or may have been caused by other respiratory pathogens. In some cases, a positive PCR result might simply have reflected transient nasopharyngeal carriage of B. pertussis.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".