Effects of the COVID-19 pandemic on self-reported 12-month pneumococcal vaccination series completion rates in Canada: An interrupted time-series analysis

Abstract

Background: Routine childhood vaccination improves health and prevents morbidity and mortality from vaccination preventable diseases. There are indications that the COVID19 pandemic has negatively impacted vaccination rates globally, but systematic studies on this are still lacking in Canada. This study aims to add knowledge on the effect of the pandemic on pneumococcal vaccination rates of children using self-reported immunization data entered into the CANImmunize digital vaccination tool. Methodology: An interrupted time series analysis was conducted on aggregated monthly enrollment of children on the platform (2016 to 2021) and their pneumococcal immunization series completion rates (2016 to 2020). Predicted trends before and after the onset of the COVID19 related restriction (March 1, 2020) were compared by means of an Autoregressive Integrated Moving Average (ARIMA). Results: Pandemic restrictions were associated with changes in self reported pneumococcal immunization rates amongst the users of the CANImmunize platform. The monthly enrollment of children on the platform decreased by 1177.52 records (95% CI: -1865.47, -489.57), with a continued decrease of 80.84 records each month. Self-reported pneumococcal immunization series completion rates had an immediate increase of 14.57% (95% CI 4.64, 24.51) followed by a decrease of -3.54% each month. Conclusion: The onset of the COVID19 related restrictions impacted enrollment of children in the CANImmunize digital immunization platform, and an overall decrease in self-reported pneumococcal immunization series completion rates. Our findings support that efforts to increase catch-up immunization campaigns so that children who could not get scheduled immunization during the pandemic are not missed.