At least 49 cases have been confirmed. Health officials — who are scrambling to get a handle on the vaccine-preventable outbreak — suspect 200 to 300 people may be infected.

The measles outbreak first reported in Gaines County, Texas, has doubled to 48 cases in the last four days, the Texas Department of State Health Services said in a statement Friday.

A growing measles outbreak in west Texas has infected 48 people, according to official state data released Friday -- the latest sign that the once-vanquished childhood disease is making a comeback as vaccination rates decline.