It is the latest milestone in the ongoing outbreak of a disease that was once thought to be eliminated in the US.

Measles cases in the U.S. have surged to alarming levels, with over 1,200 confirmed cases this year, according to Johns Hopkins University. While Texas reports the majority, Colorado has seen 16 cases,

New Jersey residents are at a greater risk for measles now that the state no longer has herd immunity. Public health experts say that measles control depends on herd immunity of 95% vaccination coverage and that rate has been declining in the U.S. and in New Jersey, while the number of people going unvaccinated climbs.