What happened on the Diamond Princess: transmission by small aerosol droplets that hung in the air.
So there you go. MASKS are the answer and the more efficient the better.
https://www.nytimes.com/2020/07/30/health/diamond-princess-coronavirus-aerosol.html
Oh, and another thing about which we were right: children do spread the virus, and carry large loads of it, as large as adults; it's just that if they're very young they don't get sick, or as sick.
So, the ones who will be at risk if schools open will be the teachers, administrators, staff etc. High school students will also become ill, but most will recover.
I'm fully aware that unless children go back to school the economy will not come back. For elementary school, when they really need guidance, and when parents really need them in a supervised setting, maybe they can reconfigure classrooms, provide "real" masks for the adults etc.
However, for middle school and high school,I would not send my children to school. They'll bring it home to everyone else. There's no need for a thirteen year old to require a babysitter. Christ, I was paying all the family bills, going to school conferences for my brother with my mother, and doing all the "business" phone calls for my family when I was thirteen because my father was always working and my mother hadn't yet picked up English. I also can't remember my parents even looking at my homework. If these teenagers aren't doing what they should be doing it's time for the parents to step in and assert the discipline they've neglected so far. If necessary, pick a few families whom you know are social distancing, and pay the most competent parent to supervise the internet work of six or seven or ten of them in someone's living room.
The government should be putting these programs and these suggestions out there so people can prepare.
The poor children who will suffer will be the ones in underclass urban and rural areas where they have no computers and no one to help them. They'll just fall further behind.
See:
https://www.nytimes.com/2020/07/18/health/coronavirus-children-schools.html
I knew that was part of the reason Italy and Spain were hit hard and Scandinavia wasn't. It's not going to be as bad where the majority of elderly people live alone and rarely see their grandchildren.