Single-dose effectiveness of mpox vaccine in Quebec, Canada: test-negative design with and without adjustment for self-reported exposure risk
Bibliographic record
Abstract
Abstract Introduction During the 2022 mpox outbreak, the province of Quebec, Canada prioritized first doses for pre-exposure vaccination of people at high mpox risk, delaying second doses due to limited supply. We estimated single-dose mpox vaccine effectiveness (VE) adjusting for virus exposure risk based only on surrogate indicators available within administrative databases (e.g. clinical record of sexually transmitted infections), or supplemented by self-reported risk factor information (e.g. sexual contacts). Methods We conducted a test-negative case-control study between June 19 and September 24, 2022. Information from administrative databases was supplemented by a questionnaire collecting self-reported risk factors specific to the three-week period before testing. Two study populations were assessed: all within the administrative databases (All-Admin) and the subset completing the questionnaire (Sub-Quest). Logistic regression models were adjusted for age, calendar-time and exposure-risk, the latter based on administrative indicators only (All-Admin and Sub-Quest populations) or supplemented by questionnaire information (Sub-Quest population). Results There were 532 All-Admin participants, of which 199 (37%) belonged to Sub-Quest. With exposure-risk adjustment based only on administrative indicators, single-dose mpox VE among All-Admin and Sub-Quest populations was similar at 35% (95%CI:-2-59) and 30% (95%CI:-38-64), respectively. With adjustment supplemented by questionnaire information, Sub-Quest VE increased to 65% (95%CI:1-87). Protection against severe outcomes was higher (VE=82%; 95%CI:-50-98) but with overlapping confidence intervals. Conclusions One vaccine dose reduced mpox risk by about two-thirds when adjustment incorporated self-reported risk factors, but by only one-third when adjustment relied solely upon administrative indicators. Inadequate adjustment for exposure risk may substantially under-estimate mpox VE.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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".