evidence: While immunization is one of the most successful public health interventions, coverage plateaued in the decade prior to COVID-19. The COVID-19 pandemic, associated disruptions, and vaccination efforts strained health systems in 2020 and 2021, resulting in dramatic setbacks. Data from 2023 show that performance has not yet returned to 2019 levels. [...] Monitoring data at subnational levels is critical to helping countries prioritize and tailor vaccination strategies and operational plans to address immunization gaps and reach every person with life-saving vaccines. WHO is working with countries and partners to improve global vaccination coverage, including through these initiatives adopted by the World Health Assembly in August 2020.