New York City will fight a Staten Island judge’s decision to strike down the school mask mandate for preschool-aged children, Mayor Eric Adams announced Friday.

He added that city attorneys would appeal the injunction and ask for a stay, after Richmond County Judge Ralph Porzio voided the rule Friday afternoon. Health department officials said they would wait another week to reassess whether to lift the mask requirement for this age group.

Test + Trace Corps has begun to distribute more than 6 million at-home COVID tests through community groups, schools, houses of worship and elected officials’ offices as a measure against BA.2, the highly contagious subvariant of omicron that has driven up COVID transmission in recent weeks. The sub-strain accounts for close to 80% of cases sequenced in the city, said health commissioner Dr. Ashwin Vasan.

The city had originally planned to drop the preschool mask mandate on April 4th, provided that COVID-19 risk levels remained low. But BA.2 has started to push the borough of Manhattan over the threshold from “low” to “medium” risk, according to a rubric created by the Centers for Disease Control and Prevention. With case rates on the rise in the city, though still in the "low" threshold and no licensed vaccine for children under 5, city health officials recommended that the decision be delayed.

“We believe we have enough evidence to win,” Adams said of the appeal process at a news conference Friday, noting that he’ll adhere to the final ruling. He and his officials said they weren’t ready to reinstate the mask mandate for older students and business patrons that he lifted early last month yet but would reconsider if cases continue to rise.

“Cases are definitively rising and it’s gotten our attention,” Vasan said. “They will continue to rise over the next few weeks. And it’s likely that over these weeks we will move into a different level of overall risk across the city.”

The city health department is reporting 1,400-plus new cases each day, more than double the mid-March count and the most since mid-February. Cases in city schools have also doubled during the same time period, according to education department data.

Health officials urged New Yorkers to get vaccinated and boosted, test regularly and mask up indoors, particularly when they’re with people whose vaccination status they don’t know. They also called on the federal government to renew much needed emergency funding for tests, vaccines and treatments.