An early look at the second dose completion of the recombinant zoster vaccine in Canadian adults: A retrospective database study
Bibliographic record
Abstract
BACKGROUND: In 2017, the two-dose recombinant zoster vaccine (RZV) was authorized for use in Canada for the prevention of herpes zoster (HZ) in adults ≥ 50 years of age (YOA), which is administered 2-6 months apart. The National Advisory Committee on Immunization (NACI) states that a 0, 12-month schedule may be considered if flexibility in the timing of the second dose is needed to improve coverage. This retrospective database study evaluated the second-dose completion of RZV in Canada from January 2018 to May 2019. METHODS: Data were obtained from the IQVIA LRx Longitudinal Prescription Database which tracks retail prescriptions of anonymized patients. Patients were followed for 6- or 12-months to evaluate the second dose completion aligned with the licensed RZV dosing schedule and NACI's option for greater flexibility. The primary outcomes were time from first to second dose and the proportion of patients who received the second dose. RESULTS: In the 6-month (155,747 patients) and 12-month (55,524 patients) analytic cohorts, 65.0% and 74.9% received the second RZV dose within 2-6 months and 2-12 months after the first dose with a truncated mean time of 97.8 days and 109.8 days between doses, respectively. Variation in completion rates was observed across age and geography, but sex, rurality, and pharmacy type did not impact results. CONCLUSION: Second dose completion of RZV in Canada is high but suboptimal. Further research to understand the factors influencing second dose timing and completion will be an important next step to improve series completion.
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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 | 0.003 | 0.010 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.011 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".