Historically, response to pandemics has affected routine immunization coverage, as exemplified in the BC childhood immunization programs during the 2009 A/H1N1 influenza pandemic. In March and April 2020, BC health authorities observed that while immunization services were being offered, parents were canceling appointments for fear of contracting SARS-CoV-2. As many routine services were canceled or deferred and physicians moved to providing virtual care, opportunities for in-person visits were further curtailed. Other jurisdictions have seen declines in childhood immunization, and international health agencies have issued a call for efforts to ensure continuity of immunization against childhood vaccine-preventable diseases.[1-4]

What has been observed in BC?

On-time immunization (defined as receipt of the recommended dose within 30 days of the milestone) of infants and toddlers was immediately affected in BC, with the greatest impact on receipt of the 12- and 18-month doses, and less effect on the infant series beginning at 2 months of age. Regions most affected by COVID-19, including the Lower Mainland, saw the greatest declines in on-time receipt of childhood vaccines, with reductions as great as 40% for the 12-month dose compared to the prior year. Also impacted were school-based immunization programs for children and youth in grades 6 and 9 in the first and second school year of the COVID-19 response, with only 27.5% of grade 6 girls and boys completing the HPV two-dose series by 30 June 2020, a decline from 67% in recent prior years.

Why is this a problem?

Priority during the COVID-19 response has been on the continued delivery of the primary DPT-containing series and other vaccines in infancy.[5] Doses given beginning at 18 months and at school entry are booster doses, and deferral is not expected to result in short-term resurgence of vaccine-preventable diseases. In adolescence, the critical new vaccines are HPV, scheduled in grade 6, and meningococcal quadrivalent conjugate vaccine, given in grade 9 prior to entry into a higher-risk age group for invasive meningococcal disease.

While BC experienced declines in vaccine-preventable diseases with the onset of travel restrictions and other COVID-19 prevention measures in place, now that these are lifting, unvaccinated and undervaccinated children will be at risk for infections. Diseases like measles, which are associated with importation, will be on the rise because of global immunization being interrupted. As we enter the third school year with COVID-19 among us, with several cohorts of children needing to catch up, it will be important to track vaccination completion by June 2022. Children who were in grade 9 in the 2019/20 school year will be starting grade 12 in September 2022. Once youth graduate from high school, opportunities to track whether they completed their vaccines are often lost.

What can physicians do to catch up children who are behind on vaccinations?

Use every opportunity to review and update child and adolescent vaccinations as these patients present for services. If you are the immunization service provider for infants and young children for your patient population, issue reminders to those who are delayed to get them caught up. Immunization records of children and youth under 19 are viewable in CareConnect as recorded in the provincial immunization registry (PIR), including the recommended forecast for that child based on their PIR record and the BC immunization schedule. A project to interface electronic medical records with the PIR is underway, but for now physicians should continue to report all doses administered to those under 19 years to their local health unit so that the PIR record can be updated.
—Monika Naus, MD, MHSc, FRCPC, FACPM
Medical Director, Communicable Diseases & Immunization Service
BC Centre for Disease Control
Professor, University of British Columbia School of Population and Public Health

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This article is the opinion of the BC Centre for Disease Control and has not been peer reviewed by the BCMJ Editorial Board.

References

1.    McDonald HI, Tessier E, White JM, et al. Early impact of the coronavirus disease (COVID-19) pandemic and physical distancing measures on routine childhood vaccinations in England, January to April 2020. Euro Surveill 2020;25:pii=2000848.

2.    Patel Murthy B, Zell E, Kirtland K, et al. Impact of the COVID-19 pandemic on administration of selected routine childhood and adolescent vaccinations - 10 U.S. jurisdictions, March–September 2020. MMWR Morb Mortal Wkly Rep 2021;70:840-845.

3.    Causey K, Fullman N, Sorensen RJD, et al. Estimating global and regional disruptions to routine childhood vaccine coverage during the COVID-19 pandemic in 2020: A modelling study. Lancet 2021;398(10299):522-534.

4.    World Health Organization. COVID-19 pandemic leads to major backsliding on childhood vaccinations, new WHO, UNICEF data shows. 15 July 2021. Accessed 8 November 2021. www.who.int/news/item/15-07-2021-covid-19-pandemic-leads-to-major-backsliding-on-childhood-vaccinations-new-who-unicef-data-shows.

5.    BC Centre for Disease Control, BC Ministry of Health. Continuity, prioritization and safe delivery of immunization services during COVID-19 response. Updated 15 October 2021. Accessed 8 November 2021. www.bccdc.ca/resource-gallery/Documents/Guidelines%20and%20Forms/Guidelines%20and%20Manuals/Epid/CD%20Manual/Chapter%202%20-%20Imms/Continuity_of_Immunization_Services_During_COVID-19.pdf.