NEW YORK (NYTIMES) - Students across the United States have begun to head back to school, starting in Atlanta this week.
But parents' hopes for a return to normal instruction in the fall have begun to evaporate as the highly contagious Delta variant drives up cases and hospitalisations.
With policymakers from local school boards to the White House scrambling to balance public health and children's learning needs, a patchwork of coronavirus rules is emerging nationwide, provoking debates, division and anxieties among families, teachers and education officials.
Some large school districts like Los Angeles are requiring all staff members to get tested for the virus each week.
States led by Democrats, including New Jersey, California and Illinois, have imposed statewide mask mandates in schools.
Meanwhile, states with Republican-controlled governments, such as Florida, Arizona and Arkansas, have forbidden districts from imposing mask rules, casting mandates as an infringement on personal freedom and parental rights.
New York City will retain its school mask requirement, but the state of New York has not imposed a statewide policy.
President Joe Biden and federal health officials have emphasised that remote learning should not be used as a strategy to counter the Delta variant surge.
Even as the Centres for Disease Control and Prevention revised their guidance last week and called for universal masking in schools, the agency stressed the need for students to return to class.
"We can and we must open schools this fall, full time," Mr Biden said recently. "It's better for our children's mental and emotional well-being, and we can't afford another year out of the classroom."
But with mask rules varying from state to state, and even within states and counties, the long-awaited return to school has many parents confused and unnerved.
"I think it's going to be really important to consider what your risk is, what the risk of a child is," said Epidemiology Professor Anne Rimoin at UCLA.
Part of that calculation, she said, is to weigh the benefits of school, both for learning and social development, against the health risks to children, most of whom are unvaccinated.
Children "benefit from being in school, but we know how to keep children safe", Prof Rimoin added.
"That's with having as many people who are eligible for vaccination around them as possible vaccinated, and wearing masks to stop transmission."
Dr Jeffrey Klausner, an expert on infectious diseases at the University of Southern California, said certain mask mandates make sense, but interventions "should be tied to the metrics".
Cases may rise as school gets underway, he said, but severe illness in children from Covid is rare.
In the last year-and-a-half, about 64,700 people in California have died from the virus. Dr Klausner said just 23 deaths were of children between five and 17 years old.
"I think the reality will be that there will be an increased number of cases," Dr Klausner said.
"But, you know, parents should be reassured that the severity of illness in children is very, very low."
Many epidemiologists and public health experts say the best way to protect school children is to get more people vaccinated.
About 60 per cent of US adults have been fully vaccinated, helping bring the total for the whole population - which includes roughly 50 million children under 12, who are not eligible - to about 50 per cent.
"It's not about me, it's not about you, it's about us and the collective good," Prof Rimoin said of vaccination.
"Getting our kids back in school is the best thing we can do for our future."