At least 124 cases of measles have been identified in Texas since late January, mostly among children and teenagers who are either unvaccinated or whose vaccination status is unknown, officials say.

A Texas measles outbreak has doubled in the last week to 124 cases, state health officials said Tuesday, a day after they warned a person infected with the highly contagious disease had traveled from the outbreak zone.

The first person known to have died from measles in the U.S. in a decade was announced by health officials on Wednesday and described as a "school-aged child" who perished in a children's hospital in West Texas,