Two dozen cases of measles have been reported in a small West Texas county that has one of the state’s highest vaccine exemption rates. In Gaines County, which has a population of about 22,000, 24 cases of the airborne infectious disease have been reported since late January. Most of them are unvaccinated, school-aged children.

The Texas Department of State Health Services has issued guidance to schools as the measles outbreak in Gaines County rises to 15 cases, mostly in children.

The Texas Department of State Health Services has identified 24 measles cases in connection with the onset of symptoms within the last two weeks. Gaines County, a small county in West Texas, has one of the highest rates of vaccine exemptions in the state.