Assessing the relationship between existing childhood, adolescent and adult immunization programmes and national COVID-19 vaccination capacities in 2021

During the COVID-19 pandemic, nearly all countries introduced COVID-19 vaccination programmes. Yet, countries had a wide range of programmatic experiences. This analysis aims to identify national characteristics associated with COVID-19 vaccination programmatic success. We used the following outcome measures: the presence of national COVID-19 vaccination capacities and COVID-19 coverage as of December 2021, June 2022, and December 2022. We developed a standardized metric for assessing national COVID-19 vaccination capacities as a proxy for speed of introduction. We developed this metric through adaptation of the WHO Guide for Conducting an Expanded Programme on Immunization Review and consultations with technical experts specializing in vaccine introduction and emergency deployment; monitoring and data; childhood, adolescent and adult programmes; and COVID-19 vaccination roll-out. Through multivariable linear regressions, we evaluated whether having a mature immunization programme for children, adolescents and adults; recent use of emergency vaccination; World Bank income classification; past early adoption of new vaccines; density of the health workforce; and/or trust in science and government were associated with higher COVID-19 vaccination capacities and coverage. The COVID-19 vaccination capacities scores ranged from 0 to 5 points with a global median score of 2 and an interquartile range of 1;4. After adjusting for World Bank income classifications, the presence of a mature influenza vaccination programme was independently correlated with statistically significant higher scores of national COVID-19 vaccination capacities and higher COVID-19 vaccination coverage in December 2021, June 2022, and December 2022. Trust in government was also associated with higher coverage for all three time stamps. As countries consider how to prepare for and respond to future pandemics, having an adult seasonal influenza vaccination programme, building trust in government, and ensuring equitable access to vaccines supply emerged as key aspects that can benefit from additional national and global focus.