Human papillomavirus vaccination patterns among youth aged 16–26 in the context of publicly-funded eligibility changes: a retrospective cross-sectional study from Alberta, Canada
Bibliographic record
Abstract
BACKGROUND: Human papillomavirus (HPV) vaccination programs in Canada primarily target school-aged adolescents (≤ 15 years) through publicly-funded, school-based delivery. In the province of Alberta, publicly-funded HPV vaccination for older youth (age ≤ 26) began with a risk-based program (i.e. availability limited to those at elevated risk for HPV infection and/or progression to disease) in 2018, expanding to an age-based program (i.e. available to all individuals within funded age groups) in July 2020. This study explores HPV vaccination patterns among 16-26-year-olds during this time period, in the context of the COVID-19 pandemic. METHODS: We conducted a retrospective cross-sectional study using population-wide administrative health data (February 2018-December 2023). Rates of HPV vaccination per 10,000 individuals were calculated by sex and age group, comparing the quarterly absolute and percent difference between the pre-pandemic risk-based period and the pandemic age-based period. We also calculated the quarterly proportion of doses delivered by sex (stratified by age group), delivery site, and individual residence (metro/urban/rural, age of arrival to province). RESULTS: HPV vaccine administration rates were higher among females than male throughout the study period (84-224 doses/10,000 compared to 40-135 doses/10,000). Rates dropped sharply after pandemic onset (March 2020), with the largest and most sustained drops among 16-17-year-olds (156 doses/10,000). Rates for 18-21 and 22-26-year-olds, who were newly eligible under the age-based program, returned to or exceeded pre-pandemic levels by 2022. Delivery site distribution shifted, with increased vaccination at post-secondary and STI health centres. Dose delivery remained consistently highest among metro residents, and individuals who entered Alberta after age 16. CONCLUSIONS: Expansion to an age-based HPV vaccination program may have mitigated pandemic-related declines in vaccination rates among older youth, though overall administration remained low. Results highlight persistent inequities by sex and geography, and underscore the importance of targeted promotion, improved service delivery, and expanded provider engagement to optimize HPV vaccine uptake outside school-based settings.
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How this classification was reachedexpand
Direct model labels (unvalidated)
Per-model category and study-design labels from the labeling rounds. They are machine output, unvalidated, and the disagreement between models ships as data. No study design here is MEDLINE-validated yet.
| Model arm | Categories | Study design | Confidence |
|---|---|---|---|
| gemma | no category Domain: not available · Genre: Empirical About the Canadian research system: no · About a Canadian topic: yes | Observational | low |
| gpt | no category Domain: not available · Genre: Empirical About the Canadian research system: no · About a Canadian topic: yes | Observational | low |
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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.006 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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, unvalidatedLabeled directly by 2 models reading the full record.
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".