Impact of the COVID-19 pandemic on routine immunization coverage of children and teenagers in Ontario, Canada
Bibliographic record
Abstract
OBJECTIVES: To assess immunization coverage for routine vaccinations in children (aged 4-7 years) and teenagers (aged 14-17 years) during the COVID-19 pandemic compared to the pre-pandemic period, in Ontario, Canada. METHODS: Retrospective cohort study using primary care electronic medical records data from the University of Toronto Practice-Based Research Network database from January 2018 to June 2022. Monthly estimates of vaccine up-to-date (UTD) coverage (defined as 1 dose of tetanus, diphtheria, and acellular pertussis (Tdap)-containing and 1 dose of measles, mumps and rubella-containing vaccines received after the 4th birthday for children; and 1 dose of Tdap-containing vaccine received after the 14th birthday for teenagers) and time series regression analysis were used to compare changes in mean coverage before and during the pandemic. We also examined if changes in coverage estimates over time were associated with sociodemographic factors. RESULTS: 30,010 children and 31,624 teenagers were included. Mean monthly UTD coverage for children decreased significantly from 48.7 % (SD 2.1) pre-pandemic (January 2018 - February 2020) to 44.3 % (SD 1.3) in mid-pandemic period (July 2020-June 2021), and remained significantly lower in later pandemic period (July 2021 - June 2022). Mean monthly UTD coverage for teenagers was 34.6 % (SD 0.9) pre-pandemic and decreased to 16.7 % (SD 0.6) in later pandemic period. When adjusted for baseline differences, teenagers from neighborhoods with higher income, lower proportions of racialized and newcomer populations and from rural areas experienced larger decreases in UTD coverage during the pandemic. No significant differences were found in UTD coverage among children across the various sociodemographic factors. CONCLUSION: Significant declines in immunization coverage for children and teenagers in Ontario were still observed by June 2022, highlighting the need to further study the long-term impact of the pandemic and implement effective catch-up interventions to increase immunization coverage and prevent outbreaks of vaccine-preventable diseases.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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".