United States health officials have recorded 5,182 confirmed measles cases, the highest national total since 1991, in a surge that is hitting children and teenagers hardest.

Figures released by the Centers for Disease Control and Prevention show children under five making up 18 percent of cases and those aged five to 19 accounting for 41 percent. Together, children and teenagers represent about 59 percent of confirmed infections. The vast majority, 4,993 cases, were linked to outbreaks rather than isolated introductions.

The climb comes as measles vaccination coverage among kindergarten pupils has fallen from 95.2 percent in the 2019 to 2020 school year to 92.4 percent in 2025 to 2026. Confirmed cases so far in 2026 are more than double the 2,289 recorded across the whole of 2025.

Measles is highly contagious and preventable with routine immunisation. Public health agencies have warned for several years that slipping school entry coverage would reopen gaps large enough for outbreaks to take hold. The latest national count turns that warning into a measured reverse of decades of progress, with families, schools and clinics now managing a disease many American parents had rarely seen.