The kids themselves probably won't die from the infection, but they certainly are a near-ideal vector to spread it to other people.
One might hypothesize that kids have done pretty well because, you know, schools have been near-uniformly closed, so their "places of employment" have been near-100% remote. I bet the COVID numbers look pretty good for work-from-home tech workers too, that doesn't mean tech workers are "nearly immune" to COVID.
It's just a numbers game and if COVID starts to pick up big time then it'll surge through schools. You're spending 8 hours a day in close contact with 8 different sets of 30 students who rotate every hour, plus crowded halls and busses and all that stuff. Then you go home to Grandma and she gets it.
It's already happening:
https://www.businessinsider.com/schools-reopen-coronavirus-s...
> Although kids are less likely to get severe coronavirus cases, mounting evidence suggests they can spread the virus. Most children have the same amount of virus in their upper respiratory tracts as adults do, according to a research letter published in the journal JAMA Pediatrics, and children under 5 may have between 10 and 100 times more virus than adults (though this doesn't necessarily mean they spread the virus more efficiently).