That was fast! 19 schools shut back down

They had barely cracked a book.

A total of 19 city schools have already emptied out their classrooms due to coronavirus cases this week — just days after reopening.

According to Department of Education data, seven schools shuttered in Queens, five in The Bronx, four in Brooklyn, two in Staten Island and one in Manhattan.

In addition, five Learning Bridges centers that provide daycare for remote learners were also closed this week along with four earlyl-earning facilities.

Another Staten Island school was shuttered for coronavirus cases in the week prior to the reopening, according to the Department of Education.

Roughly 850 schools for students in grades K-5 and pre-K — along with some specialneeds buildings — resumed in-person learning Monday, when the DOE launched a renewed COVID-19 testing regime for students and staff that triggered the fresh closures.

So far this year, 479 schools have been temporarily locked up at some point due to coronavirus infections.

The DOE reported 55 new student positives and 58 staff cases on Thursday.

So far this year, 2,028 students and 2,563 staff have tested positive for the virus, according to DOE numbers.

As part of his school reopening plan, Mayor de Blasio instituted a more stringent mandatory testing program.

De Blasio has asserted that increased testing helps to guard against COVID-19 outbreaks in the country’s largest school system.

“We have strict protocols in place to keep our schools safe and we don’t hesitate to thoroughly investigate and take quick action if there is a positive case reported in the building,” said DOE spokesperson Miranda Barbot.