While immunization is one of the most successful public health interventions, coverage has plateaued over the last decade. The COVID-19 pandemic, associated disruptions, and COVID-19 vaccination efforts strained health systems in 2020 and 2021, resulting in setbacks. In 2023, DTP (diphtheria, tetanus toxoid and pertussis-containing vaccine) immunization coverage had not yet recovered to 2019 levels.

DTP3 (third dose of DTP containing vaccine) immunization coverage among one-year-olds worldwide dropped from 86% in 2019 to 81% in 2021, and then recovered to 84% in 2023. Still 14.5 million infants did not receive an initial dose of DTP vaccine, pointing to a lack of access to immunization and other health services, and an additional 6.5 million are partially vaccinated.

Measles, because of its high transmissibility, acts as a “canary in the coalmine”, quickly exposing any immunity gaps in the population. Still 22.2 million children missed their routine first dose of measles, far from 2019 levels with 19.3 million.