The data show reported yellow fever case counts and calculated incidence rates aggregated at the country, WHO regional, and global levels. Data are submitted by member states through the WHO/UNICEF Joint Reporting Form on Immunization and updated continuously as country reports are received. Historical data are preserved and retroactively updated as submissions are revised. The data is viewable and filterable by WHO region and year through an interactive dashboard interface. The portal also supports cross-disease comparison, allowing yellow fever trends to be viewed alongside reported cases and incidence for other vaccine-preventable diseases tracked through the same system.