Many students in kindergarten through 12th grade are out sick because of Covid-19 or are being kept home by anxious parents, as the Omicron variant surges, officials say. Remote learning often isn’t being offered anymore for students who are home. Empty desks create a quandary for teachers, who must decide whether to push ahead with lesson plans knowing a large number of their students will need to catch up.

New York City, the nation’s largest school district, saw its overall attendance rate fall below 70% when classes resumed after the winter holidays, far beneath the district’s pre-pandemic average of over 91% students at school each day. Many students missed class because of fears of contracting the virus or because they or a family member had tested positive, teachers said.

“There’s never been anything like this,” said Arthur Goldstein, a teacher at Francis Lewis High School in Queens, N.Y., referring to the sustained low attendance. He has taught in New York City for 37 years and held classes in the aftermath of disasters, including the Sept. 11, 2001, terrorist attacks and superstorm Sandy in 2012.