COVID-19 and missed routine immunizations: designing for effective catch-up in Canada.

COVID-19 has led to disruption in routine immunization programs around the globe and here in Canada. The National Advisory Committee on Immunization (NACI) in Canada has indicated that this sets the stage for serious outbreaks of vaccine-preventable diseases. The World Health Organization has evidence-based guidance on how to address missed opportunities for vaccination, albeit predominately applicable for low- and middle-income countries. In Canada, immunization applies beyond infant and childhood immunization, with immunization across the life course being recommended by NACI. Three components stand out and must be integrated and used concurrently for best effect on catch-up in Canada: (1) Identify who has been missed across the life course; (2) detect delivery gaps, adapt and adjust, and develop multipronged tailored strategies for catch-up; and (3) communicate, document, evaluate and readjust the immunization programs. All must be adapted to the reality of the evolving COVID-19 pandemic. We cannot go back to a pre-COVID-19 world. However, ensuring that routine immunization and catch-up programs are done well during this pandemic strengthens the immunization foundation in Canada for when COVID-19 vaccines become available.