Impact of the COVID-19 pandemic on routine childhood and other primary care immunizations in Ontario, Canada

Vaccines are one of the most important public health interventions to protect at-risk patients, such as children and older adults with comorbidities, from serious infections. The COVID-19 pandemic has made it difficult to provide health services as usual, including vaccines. Studies all around the world have reported declines in immunization coverage in 2020, but there is still limited data in Canada. Our team recently completed a project on the impact of COVID-19 on routine immunization coverage in children under 2 years old in Ontario, using primary care electronic medical records data from the UTOPIAN database from January 2019 to December 2020. Our study found that immunization coverage rates for children under 2 significantly decreased during the early period of the pandemic and only partially recovered during the rest of 2020, and that some subgroups of children experienced larger declines in coverage and should be prioritized in immunization catch-up interventions. Building on this work, we want to expand our analyses to trend the childhood immunization coverage rates from 2018 to 2021 and look at other immunizations routinely given in primary care settings. These include tetanus and measles vaccines for children 4-6 years old, tetanus vaccine for teenagers (14-16 years old), tetanus/pertussis vaccine during pregnancy, pneumococcal vaccine for adults > age 65, especially in adults with medical conditions like heart diseases, diabetes and lung diseases. We will also do a survey study and interviews with patients and parents to understand the barriers and facilitations to accessing vaccination services during the pandemic. We will generate evidence to understand the extent of the indirect health consequences of COVID-19 on routine immunization coverage for at-risk populations, to identify factors (individual, provider, community-level, etc.) associated with coverage gaps and to inform targeted interventions to catch-up or prevent immunization delays.