After a string of school closures so far this year, Philadelphia health officials on Wednesday relaxed guidelines for when schools should temporarily close due to COVID-19 cases – while also calling for weekly tests for unvaccinated students throughout the district.

Schools are advised to consult with the Department of Health about closing a class if there are six cases in the classroom – or closing a school if three classes are closed, or if the cases are reach 3% of a school’s population, according to the Philadelphia Department of Public Health.

Under previous ministry directives, six cases in one school warranted a switch to virtual education. That threshold was stricter than state guidelines and triggered a number of closures: As of Tuesday, five schools in the city were closed, according to health officials. A sixth had already closed but reopened.

Cheryl Bettigole, the city’s acting health commissioner, said on Wednesday that the new guidelines “are less stringent than our previous guidelines because we have seen that our other security measures have been successful in containing the spread.”

READ MORE: How do schools decide to close due to COVID-19 cases? Everything depends.

Bettigole also said she looked at “what we were doing compared to other places, how many schools we ended up closing. And, see the reality on the ground of what the cases are. “

The department also changed its guidelines to allow students to “test to stay,” allowing some children who are close contacts to stay in school rather than self-quarantining if they test negative for the virus. But schools must offer rapid on-site testing in order to enable the option.

The ministry is also now recommending that schools test unvaccinated students weekly.

The changed guidelines are likely to have a significant impact in the Philadelphia School District, which has 115,000 students, most of whom are unvaccinated. It’s unclear who would test students in the district – school nurses are currently administering tests to children who show symptoms during the day, but many already report being unable to complete all of their current duties due to COVID-19 responsibilities .

District officials were not immediately available for comment.

This is a developing story.