Impact of the COVID-19 pandemic on routine immunization coverage in children under 2 years old in Ontario, Canada: A retrospective cohort study. Issue 12 (15th March 2022)

• Record Type: Journal Article
• Authors: Ji, Catherine; Piché-Renaud, Pierre-Philippe; Apajee, Jemisha; Stephenson, Ellen; Forte, Milena; Friedman, Jeremy N.; Science, Michelle; Zlotkin, Stanley; Morris, Shaun K.; Tu, Karen
• Is Part Of: Vaccine. Volume 40:Issue 12(2022)
• Page Start: 1790
• Page End: 1798
• Publication Date: 2022-03-15
• Subjects: Immunization coverage -- Childhood immunization -- COVID-19 -- Primary care -- Family medicine -- Pediatrics -- Health services -- Retrospective observational study; EMR Electronic Medical Records -- GTA Greater Toronto Area -- SES Socioeconomic Status -- UTOPIAN University of Toronto Practice-Based Research Network -- VPDs Vaccine Preventable Diseases; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2022.02.008
• Languages: English
• ISSNs: 0264-410X

Abstract

Abstract: Background: The COVID-19 pandemic has caused a disruption in childhood immunization coverage around the world. This study aimed to determine the change in immunization coverage for children under 2 years old in Ontario, Canada, comparing time periods pre-pandemic to during the first year of the pandemic. Methods: Observational retrospective open cohort study, using primary care electronic medical record data from the University of Toronto Practice-Based Research Network (UTOPIAN) database, from January 2019 to December 2020. Children under 2 years old who had at least 2 visits recorded in UTOPIAN were included. We measured up-to-date (UTD) immunization coverage rates, overall and by type of vaccine (DTaP-IPV-Hib, PCV13, Rota, Men-C-C, MMR, Var), and on-time immunization coverage rates by age milestone (2, 4, 6, 12, 15, 18 months). We compared average coverage rates over 3 periods of time: January 2019-March 2020 (T1); March-July 2020 (T2); and August-December 2020 (T3). Results: 12, 313 children were included. Overall UTD coverage for all children was 71.0% in T1, dropped by 5.7% (95% CI: −6.2, −5.1) in T2, slightly increased in T3 but remained lower than in T1. MMR vaccine UTD coverage slightly decreased in T2 and T3 by approximately 2%. The largest decreases were seen at ages 15-month and 18-month old, with drops in on-time coverage of 14.7% (95% CI: −18.7, −10.6) and 16.4% (95% CI: −20.0, −12.8) respectively during T2. When stratified by sociodemographic characteristics, no specific subgroup of children was found to have been differentially impacted by the pandemic. Conclusion: Childhood immunization coverage rates for children under 2 years in Ontario decreased significantly during the early period of the COVID-19 pandemic and only partially recovered during the rest of 2020. Public health and educational interventions for providers and parents are needed to ensure adequate catch-up of delayed/missed immunizations to prevent potential outbreaks of vaccine-preventable diseases.