At least 124 cases have been reported since late January, mostly among children and teenagers who were unvaccinated or whose vaccination status was unknown.

The current outbreak is centred in north-western Texas, with measles also recently found across the state's border in New Mexico, as well as Alaska, California, Georgia, New Jersey, New York City and Rhode Island,

The director of public health in Lubbock, Texas, confirmed that one child has died of measles, the first death related to the disease in the U.S. in a decade. NBC News’ Sam Brock reports on how the medical community is reacting to the rise of a disease that was considered eliminated in the U.