Nine of those infected were hospitalized and more cases are likely, health authorities said. U.S. vaccination rates for measles are falling, according to the CDC.

As Gaines County, Texas, deals with a measles outbreak, experts are reminding Americans that outbreaks like these can be avoided with available safe and effective vaccines.

As of Tuesday, 22 children and two adults had been infected, all of whom were unvaccinated, local officials said.