"The schools are where kids are safe. A lot of parents, if the school's not there, the parent can't go to work, especially in a single-parent household," de Blasio said in an in-depth interview on the FOX 5 morning show Good Day New York. "You can't bring your kid to work in most places."
He said it was a critical resource for families to keep the city running.
"The city has to keep going. We need people to have their livelihoods. We need people to show up at work. We need our public servants to be where they need to be to take care of folks," de Blasio said.
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But some city officials and the union representing teachers say the schools should close.
"Teaching and learning can not take place under these circumstances for the safety and well being of the teachers and students," City Council Speaker Corey Johnson said in a statement Friday.
Saying that the union doesn't make this suggestion "lightly," UFT President Michael Mulgrew urged the city should follow the example of other communities around the world.
"We understand the immense disruption this will create for our families. But right now more than a million students and staff crisscross the city every day on their way to schools, putting themselves and others at risk of exposure and increasing the likelihood of bringing exposure into their homes and communities," Mulgrew said. "Many local area schools, religious and public, have already closed, as have schools in the entire states of Michigan, Maryland, Ohio and Kentucky. The schools of entire countries have been closed to help contain the spread of the virus."
About 700,000 children in the New York City public school system live in poverty conditions.
"When kids go to school, it's not just about their education, which I don't want to interrupt," Mayor de Blasio said. "I don't want to see kids miss weeks or months of school. It's where a lot of kids get their meals. A lot of kids who are less-advantaged really depend on the schools for meals."
The mayor added, "The city has to keep going. We need people to have their livelihoods. We need people to show up at work. We need our public servants to be where they need to be to take care of folks."
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He continued, "We have to have a workforce in our hospitals, in our clinics, our first responders. We need them, especially in this moment. They need their kids to be in school so they can show up to work. This is a big part of the equation."
Mayor de Blasio did leave the door slightly open to closing schools at a later date.
"We will take steps as needed," de Blasio said.
The mayor said the number of cases in the city did not jump overnight and sit at 95 as of Friday morning.
"For the vast majority of people, first of all, if you even got coronavirus, but you're healthy and you don't have those pre-existing conditions, most people will experience it. 80% is the global experience right now, will experience it like cold or flu."
De Blasio said he predicts that the virus will impact the city for six months until the crisis is receding.
"It's going to be a long battle. Nothing I'm saying is to minimize the danger. People are going to suffer," de Blasio said. "We're going to lose some people. There's no question. I say that with pain. But the truth is also, New Yorkers can handle it."
"We must find ways to keep our children safe, and to see that they are fed. We must do all we can to help ensure that our students can continue to learn," the UFT's Mulgrew said. "But we have reached the point where continuing to keep our classrooms open poses a greater lasting threat than the disruption that will result from school closings."