The declaration comes as outbreaks of measles have cropped up around the country, concentrated in populations with low vaccination rates in places like ultra-Orthodox Jewish communities in Brooklyn and tight-knit Slavic communities in Washington state.
But Rockland County’s order, one of the most aggressive steps taken since the New York outbreak began last fall, highlighted not just the seriousness of the situations but also the desperation of public officials to control the spread of a highly contagious disease they have so far been powerless to halt.
The declaration will take effect at midnight on Tuesday and expires in 30 days. The prohibition will be enforced retroactively, with parents being penalized if they are found to have allowed unvaccinated children into the public spaces.
The county executive, Ed Day, was expected to discuss the details of the state of emergency in a news conference at 2 p.m.
Rockland County, which has a population of more than 300,000 people, has had 153 confirmed cases of measles since October, a county spokesman, John G. Lyon, said. Of those, 48 have come in 2019.
The outbreak there, as well as in New York City, has mostly affected ultra-Orthodox communities, where vaccination rates tend to be lower and anti-vaccination literature has spread, public health officials have said.
In December, in an effort to stop the spread of diseases, Rockland County issued exclusion orders barring unvaccinated children from schools with low vaccination rates. In New York City, health officials also issued an emergency health measure ordering that schools in certain ZIP codes stop unvaccinated students from attending classes.
But as public health officials in Rockland County worked to trace the outbreak, they also found possible instances of measles exposure in supermarkets, stores and shopping centers.
In addition to New York, there have also been measles outbreaks in Washington state, Texas, Illinois and California, the CDC said.
This article originally appeared in The New York Times.