Michigan has in recent weeks seen at least eight schools shut down or return to online learning because of staff shortages. In Florida, Brevard Public Schools said Wednesday it would extend its Thanksgiving break, while public schools in Seattle and Portland, Oregon, gave teachers and students an extra day off for Veterans Day.

Administrators acknowledge the last-minute schedule changes are forcing parents to scramble their own plans, and it’s the latest obstacle for students trying to make up missed learning following widespread pandemic school closures. Experts say missing more school means some kids, particularly those from low-income families, will fall even further behind their peers.

But they also say teachers burned-out from pandemic instruction desperately need time to recharge after another tumultuous year filled with masks, testing, sickness and ongoing public-policy battles, along with trying to help students still learning how to be back in a classroom.