The number of measles cases associated with an outbreak in western Texas has grown to 400 cases amid reports of some children taking unhealthy amounts of vitamin A.

Earlier this year, the Texas Department of State Health Services reported an outbreak of measles that began in the South Plains and Panhandle regions of Texas. As of Friday, March 28, 400 cases have been identified since late January and 41 of those diagnosed have been hospitalized.

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.

A measles outbreak spanning Texas, New Mexico and Oklahoma reached at least 453 cases Friday and might be linked to cases in other states and across borders.

Measles cases in the U.S. neared 500 Friday, according to the CDC, as the highly contagious illness continues spreading in Texas after being reported in at least 18 other states.

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.