Apparently, the American CDC (which has dubious credibility under Trump) argues that it could be more dangerous to close schools than keep them open, because the rampaging students on the streets could help spread it throughout society. This concern indicates a lack of knowledge of the behaviour of modern children. As explained on Twitter:
Now, I have to admit, if you are talking young primary school children, and there is no way you can get a healthy, younger adult to babysit them, there would be a risk of the foolhardy grandparents who offer to do the job catching it from the (quite possibly) asymptomatic grandkids. But, as I was saying to someone trying to work yesterday, when I were a lad, being left home alone for a few hours was not a very controversial thing once you were aged about 7 or 8. In Western countries (not so much in Asia, where they positively like sending kids out on the street from an early age to teach them independence and common sense) we have become too scared of leaving them alone anywhere. So a lot of primary school kids should be able to be left home alone.
But back to the evidence - this interview in Science about how and when to close schools is really good, and makes a strong case for pre-emptive closures to slow it all down:
Q: How about proactive school closures, before there are any infections associated with a school? Are they helpful?The simple suggestion as to when to close?:
A: Proactive school closures—closing schools before there’s a case there—have been shown to be one of the most powerful nonpharmaceutical interventions that we can deploy. Proactive school closures work like reactive school closures not just because they get the children, the little vectors, removed from circulation. It’s not just about keeping the kids safe. It’s keeping the whole community safe. When you close the schools, you reduce the mixing of the adults—parents dropping off at the school, the teachers being present. When you close the schools, you effectively require the parents to stay home.
There was a wonderful paper published that analyzed data regarding the Spanish flu in 1918, examining proactive versus reactive school closures. When did [regional] authorities close the schools relative to when the epidemic was spiking? What they found was that proactive school closing saved substantial numbers of lives. St. Louis closed the schools about a day in advance of the epidemic spiking, for 143 days. Pittsburgh closed 7 days after the peak and only for 53 days. And the death rate for the epidemic in St. Louis was roughly one-third as high as in Pittsburgh. These things work.
Q: How should jurisdictions decide when to pursue a proactive closing?
A: How many cases are there in the region? And what is the epidemiologically relevant region? If you’re in a mid-sized town you might say, as soon as there’s a community-acquired case in my town, whether it’s in my school or not, I’m closing my school.
There is also this good point:
Q: Are there social distancing efforts short of closing schools, especially if there are no cases associated with a particular school? For example, canceling big events that bring together lots of families?So, my "how hard it is to be an expert? I've studied this for the last hour" approach is to recommend intermediate steps, as I already proposed a day or two ago, as follows:
A: Yes, I’m so glad you mentioned that. We don’t have to have an all-or-nothing policy. We can have intermediate steps. For example, why not allow families who want to keep their kids home keep them home? Why not cancel all activities, like sporting events and musical performances that have large groups present?
a. Close down the secondary schools in nearly all of Australia now. No one going to a secondary school has to be babysat at home, so it won't stop any whose parents are nurses or health care workers from doing their job. Those parents who can work from home should, and supervise that their teenage kids are actually doing something about being glued to their phone in their room all day.
b. For now, leave primary schools open, but institute mandatory temperature taking, amending legislation to do so if necessary. (I was told by a primary school teacher that they are not allowed to take a child's temperature!) This is how Singapore kept their schools open. And it is why it is a bit
spurious of any expert to be using Singapore as an example of a successful virus containment country which did not close all schools if we cannot do the same things in the school here. Kids with a temperature are sent home to be kept there in quarantine. Employers will have to cope with the reduction in employees who have no choice but to stay at home with their under 8 year olds.
See, I've got it all worked out.
Update: from someone else at Twitter: