In the U.S., most states now are below the 95% vaccination threshold for kindergartners — the level needed to protect communities against measles outbreaks.

The United States has registered its first death from measles since 2015, after a child who wasn’t vaccinated died in an outbreak in rural West Texas. Normally, most US cases are brought into the country by people who have travelled overseas.

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 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,

An unvaccinated school-aged child in Texas has died of measles, the first associated with an outbreak that has infected more than 100 people.