As of February 5, 2026, the United States has reported 733 confirmed measles cases this year, according to data released by the U.S. Centers for Disease Control and Prevention (CDC), a figure four times the country's typical annual average. 

The CDC said most outbreaks nationwide are occurring in communities with low vaccination coverage or among unvaccinated populations.

In recent years, vaccination rates for measles, mumps and rubella (MMR) among kindergarten-aged children in the United States have continued to decline, making it increasingly difficult to achieve herd immunity.