Abstract
Few studies have assessed the impact of the COVID-19 pandemic on immunization coverage for adolescents, and little is known about how coverage has changed throughout the pandemic. We aimed to: (1) assess the change in coverage for school-based vaccines in Alberta, Canada resulting from the pandemic; (2) determine whether coverage differed by geographic health zone and school type; and (3) ascertain whether coverage has returned to pre-pandemic levels. Using a retrospective cohort design, we used administrative health data to compare coverage for human papillomavirus (HPV) and meningococcal conjugate A, C, Y, W-135 (MenC-ACYW) vaccines in Alberta, Canada between pre-pandemic (2017-2018 school year) and pandemic (2019-2020 and 2020-2021 school years) cohorts (N=289,420). Coverage was also compared by health zone and authority type. The 2019-2020 cohort was followed over one year to assess catch-up. Compared to 2017-2018, immunization coverage for HPV was significantly lower in the 2019-2020 (absolute difference: 60.8%; 95% CI: 60.4-61.3%) and 2020-2021 cohorts (absolute difference: 59.9%; 95% CI: 59.4-60.3%). There was a smaller, significant decline in MenC-ACYW coverage comparing 2017-2018 to 2019-2020 (absolute difference: 6.1%; 95% CI: 5.6-6.5%) and 2020-2021 (absolute difference: 32.2%; 95% CI: 31.6-32.7%). Private schools had low coverage overall, while coverage fluctuated by zone. During follow-up of the 2019-2020 cohort, coverage for HPV and MenC-ACYW increased from 5.6% to 50.2%, and 80.7% to 83.0%, respectively. There was a substantial decrease in school-based immunization coverage during the COVID-19 pandemic, and coverage has not returned to pre-pandemic levels, suggesting further catch-up is needed.
Competing Interest Statement
The authors have declared no competing interest.
Funding Statement
This work was supported by an operating grant from the Canadian Institutes of Health Research (grant number: VR5-172700). HS received a WCHRI graduate studentship funded through the Stollery Childrens Hospital Foundation through the Women and Childrens Health Research Institute. The funding source had no role in the study design, data collection, analysis, or interpretation, the writing of the report, or in the decision to submit the paper for publication.
Author Declarations
I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.
Yes
The details of the IRB/oversight body that provided approval or exemption for the research described are given below:
The Health Research Ethics Board of the University of Alberta gave ethical approval for this work
I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.
Yes
I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).
Yes
I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.
Yes
Data Availability
The steward of the data used in this study is the Alberta Ministry of Health, who maintains the data for the purpose of health system administration. Thus, the authors are not at liberty to make the data publicly available.
Abbreviations
- AHCIP
- Alberta Health Care Insurance Plan
- CI
- confidence interval
- COVID-19
- coronavirus disease 2019
- HPV
- human papillomavirus
- Imm/ARI
- Immunization and Adverse Reaction to Immunization
- MenC-ACYW
- meningococcal conjugate A, C, Y, W-135
- PSIR
- Provincial School Immunization Record
- SD
- standard deviation.