A measles outbreak in Texas has grown to 159 cases, and the US Centers for Disease Control and Prevention says it is now on the ground in that state to respond. The agency posted on X that it’s partnering with the Texas Department of State Health Services.

Vaccination eliminated measles from the U.S. 25 years ago. But it can still spread in pockets where vaccination rates are low, like the west Texas county with a current outbreak. Here's how fast.

Many doctors have never seen measles in person. The Texas outbreak is reshaping how health systems prepare for drops in vaccinations.