With one school building already closed a week into the academic year, the city will increase coronavirus testing in public schools, but will also require fewer children to quarantine, Mayor Bill de Blasio announced on Monday. 

The city will move to weekly testing at all elementary, middle and high schools starting on Sept. 27, the same day a vaccine mandate for adult staff is set to go into effect. The city started off the school year saying they’d test students every two weeks, which many parents and educators deemed insufficient. The city's teachers' union called on Sunday for weekly testing.

In another big change, the city will drop its policy of quarantining an entire classroom in response to a positive case of COVID-19, a stance that was more conservative than the Centers for Disease Control recommendations. Beginning on Sept. 27, the city will follow the CDC guidelines: unvaccinated students who are close contacts to a positive student will not have to quarantine as long as they are masked, which is required in schools, and they keep three feet of distance.

The DOE says the alignment to the CDC’s policy will “help to keep our school communities whole.”

At a Monday morning news conference, de Blasio said the changes were prompted by the number of quarantines the city has seen since the beginning of the school year. 

The initial policy of quarantining entire elementary school classes and unvaccinated students in middle and high schools had led to 441 classrooms currently being fully closed, and another 338 partial closures.

The city has already closed one full school building, P.S. 79 in East Harlem.

"This is a conversation that has been going on for several weeks," de Blasio said. "But we wanted to see what happened in the first week of school."

City health leaders said at the news conference that the new rules will allow for fewer classroom closures and child-by-child quarantine decisions, based on each student's proximity to and duration of contact with a student in their class who tested positive. 

"These will all be individualized decisions made in the context of cases," said Dr. Mitchell Katz, the CEO of NYC Health+Hospitals, and the head of the city's test-and-trace effort. "Just because one group of children are together closer than three feet, doesn't mean they are exposed to the case."

De Blasio said that he does not expect to issue a blanket vaccination mandate for students this year, even as health experts and government officials expect the FDA to issue full authorization for the Pfizer vaccine for children aged 5 to 11 years old by as soon as Halloween. 

Ahead of the start of the city's vaccination mandate for education staff on Monday, schools Chancellor Meisha Ross Porter said that 78% of education department staff have been vaccinated. She added that the department has received relatively few religious and medical exemptions for vaccination, and that they do not expect a wave of teacher absences next week. 

"We are not seeing something that would have a profound impact on the teacher corps numbers for next Monday," she said.