At least five states have active measles outbreaks as of Friday, and Texas' is the largest with 400 cases. Already, the U.S. has more measles cases this year than in all of 2024, the U.S. Centers for Disease Control and Prevention has said.

When Texas officials first discovered measles cases this year, they were among the Mennonite population. Now, officials say cases are spreading to other communities.

Texas and New Mexico health departments said on Friday that the number of measles cases in their states rose 20% since their last reports three days ago, as experts warn they expect the outbreak to further spread in coming weeks.