What to Know The city is no longer making exceptions for religious or medical reasons when it comes to attending school without the measles vaccine

The health department says students who are unvaccinated won't be allowed to attend school at yeshivas in Williamsburg or Borough Park

It comes amid a measles outbreak affecting 39 people so far in those areas

Amid a measles outbreak in the Orthodox Jewish communities of Williamsburg and Borough Park in Brooklyn, the city health department is ordering unvaccinated students to stay home from school at certain yeshivas beginning on Friday.

There have been 39 cases of measles in those neighborhoods, only three of them adults, according to the health department. The median age of the children with measles is 2 years old.

The health department sent a letter to principals of yeshivas in the affected neighborhoods, telling them that every student who's not vaccinated with the required number of doses of measles-mumps-rubella vaccine won't be permitted to attend school, regardless of whether a case of measles has occurred in the sschool.

Students won't be able to return to school until they're appropriately vaccinated, or until the outbreak is declared over, even if they have an approved religious or medical exemption to measles immunization.

The new policy, effective Dec. 7, marks a change from the old exception allowing for religious and medical reasons for non-immunization.

Yeshiva principals and directors are responsible for enforcing compliance in the vaccination rule, and health officials will be auditing the yeshivas, the city says.

The health department says their audits so far show only 2 percent of children in the Orthodox communities are unvaccinated for religious or medical reasons. The overwheming majority are vaccinated.