NEW CITY, N.Y. (CBSNewYork) – A state of emergency is now in effect in Rockland County as officials attempt to contain a measles outbreak.

A ban went into effect overnight prohibiting unvaccinated children from public spaces.

Anyone under the age of 18 who has not been vaccinated for measles will not be allowed in places like shops, restaurants, schools and houses of worship for the next 30 days – or until they get their shots.

“This is a public health crisis, and it is time to sound the alarm and take the appropriate action,” Rockland County Executive Ed Day said Tuesday. “You need to be responsible for your children, you need to do the right thing for your community.”

Watch: Rockland County Officials Declare Measles State Of Emergency

There have been 153 confirmed measles cases across the county in the past six months.

“It’s your responsibility for yourself, for your family, and for your friends and neighbors to do the right thing and get the required vaccines,” said Yossi Gestener, with the Orthodox Jewish Public Affairs Council.

CBS2 asked Gestener if there is a religious reason not to vaccinate.

“It’s a bologna excuse by some people,” he said. “There are always people who think that they know better, that they understand better, and they make unilateral decisions, which obviously is reckless to do when it involves other people.”

Web Extra: Read the State of Emergency Declaration (.pdf)

Warning signs about the ban have gone up around the area. The goal is to keep the unvaccinated from encountering the measles virus, which can live for hours on hard surfaces.

“The focus is not arrest and put people in jail,” said Day. “The purpose of this is to have people comply with the law and comply with the vaccinations.”

The department of health is offering free vaccinations Wednesday afternoon.

For more information, click here. Learn more about the measles here.