Estimation of childhood vaccine scale-up rates by country and vaccine

Abstract

Background The development and integration of new vaccines into national immunization schedules has dramatically reduced the number of children experiencing preventable morbidity and mortality. Introduction and scale-up of these newer vaccines remain global health priorities, featured in global vaccine targets like the Immunization Agenda 2030 (IA2030). Analyses of country-specific scale-ups for six childhood vaccines provide insight into trends and trajectories of current delivery systems. Methods Using meta-regression – Bayesian, regularised, trimmed (MR-BRT), we estimated newer vaccine coverage controlling for underlying Expanded Programme on Immunization (EPI) vaccine coverage and years of vaccine introduction utilizing data from the Global Burden of Diseases, Injuries and Risk Factors Study 2020, Release 1. Scale-ups occurring between 1980-2019 were assessed using EPI reference coverage aligned by country and calendar year. We analyzed relationships between scale-up, national government spending on immunization, and Gavi support status. Findings First-dose rubella-containing vaccine (RCV1) had the highest scale-up in the first year of introduction (94.3%) compared to completed Rotavirus (RotaC; 40.6%) and third-dose pneumococcal conjugate vaccine (PCV3; 52.4%). RotaC was the only vaccine to not reach 95% scale-up at any point in the estimated time series. High variation in vaccine scale-up in the first year of introduction was observed across the distribution of available dollars per capita of national government spending, and countries currently experiencing Gavi support in 2019 demonstrated at least 95% scale-up for 5 of the 6 estimated vaccines. By 2019, only 75 (36.8%) of 204 estimated countries had all six vaccines introduced. Interpretation Differences in scale-up between vaccines emphasize the need for context-specific strategies prioritizing immunization equity. These findings also highlight that both vaccine introductions and scale-ups must be improved in addition to bolstering existing routine immunization delivery systems more broadly. Continued assessment, then implementation, of such approaches will be necessary to meet the IA2030 targets.