Why have measles cases returned, and what do the WHO figures show?

Measles has returned in many places because vaccination coverage has slipped, and a disease this contagious, where one case can infect up to 18 others, needs very high coverage to stay away. According to the World Health Organization (WHO), the proportion of children receiving a first dose of measles vaccine was 84 percent in 2025, slightly below the 2019 level of 86 percent. In 2025, 77 percent of children received both recommended doses, and WHO and UNICEF estimated that approximately 29 million infants remained under-protected.

Several things pushed in the same direction. The COVID-19 pandemic hindered vaccination campaigns in at least 68 countries, and in February 2024 WHO warned that more than half of the world was at risk of an outbreak because of disrupted health systems and vaccination schedules. Reported cases plateaued at 132,000 in 2016 and rose to 874,000 by 2019. Europe reported 127,350 cases in 2024, the highest in the region since 1997. In 2025 Canada lost its measles-free status after 5,462 cases; the source attributes this to coverage falling from 90 percent in 2019 to 82 percent in 2022 and 2023. In the United States, the Centers for Disease Control and Prevention (CDC) had logged 2,318 cases by July 2026, the worst year in more than three decades.

The long-run picture is still one of progress. WHO says vaccination prevented an estimated 59 million deaths between 2000 and 2024. Yet it also reports about 95,000 measles deaths in 2024, mostly of children under five, and its expert advisers concluded that measles elimination is under threat, as the disease resurged in numerous countries that had achieved, or were close to achieving, elimination.