The measles outbreak in the South Plains region, in West Texas, has expanded to at least 48 people, most of them children.

Most of the infections have shown up in Gaines County. Texas health officials have consistently said that vaccination is the best way for people to avoid the highly contagious airborne disease.

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.