Julie Storjohann, a school nurse in Washington State, spends her days toggling between numerous spreadsheets — for students who have symptoms of Covid, students who have family members who tested positive and students who have been flagged as close contacts of other students with Covid, all of which have different quarantine and testing requirements.

“I am exhausted,” she said. “I was hoping this year was going to be a little better than last year, but it’s actually worse.”

When a student tests positive, Ms. Storjohann begins a laborious contact-tracing process, which can include trying to determine whom the student sat next to at lunch or on the bus. Students have assigned seats on the school bus, she said, but do not always stay in them, so she pores over video footage from inside the bus.

“And I’m supposed to be able to pick out this student and who is around him,” she said. “And they’re wearing a mask, and they’re wearing a hood and hat, and it’s impossible.”