Young children are not at risk, unlike the flu.

They have zero fatalities so far. But don't for one second believe that having double pneumonia is a walk in the park and the lung tissue scars will be with you for life. I had pneumonia when I was 24 and to this day I have my reminders of that event. You end up with reduced lung capacity, scarring and you'll be more vulnerable to re-infection.

less at risk is not the same as not at risk. At any rate there are children that have immunity problems that as the virus spreads I worry it will effect them - for example MBL deficiency and it's susceptibility to respiratory ailments https://ghr.nlm.nih.gov/condition/mannose-binding-lectin-def... https://academic.oup.com/jid/article/191/10/1697/789682

I think you are taking common idiomatic English and interpreting it as though it is meant to be precise.

"Not at risk" does not mean 0 risk, it means negligible risk.

For example, if I was standing on a cruise ship, am I at risk for drowning? Not really, it's extremely unlikely that I would drown. Could I drown? For sure, I could fall in the ocean, or in the pool, or pass out into a bowl of soup. Despite the nonzero possibility of drowning, if someone saw me on the cruise ship waiting in line for the buffet and yelled "be careful, you are at risk of drowning" at me, I would think they had lost their mind.

But as long as you just keep standing on the deck, you're not going to drown.

But even though the risk of infection is low, I wouldn't say that a child is "not at risk" of contracting the disease if their dad catches it at work and brings it home.

I'd say that he's "at low risk", not "no risk".

Again, not at risk means not at risk. "At risk" means more than average risk. Not at risk means the opposite in common usage, it means much below average. Nobody said anything about "no risk". "low risk" and "not at risk" mean exactly the same thing.

https://www.macmillanthesaurus.com/at-risk

It seems like children are 10 times less likely to get it, though that's very rubbery numbers (based on children being 2% of cases in China despite being about 20% of the population, not that I really trust the numbers are accurate). A 0.1% chance of death (or even 0.01%) is still concerning.

The problem with MBL deficiency which can be a problem among younger children is that it makes you more susceptible to catching respiratory ailments and suffering worse from them. So as this is still in early stages we might not know how it effects children with MBL deficiency, it might be very bad for them.

Young children are quite touchy among peers and great at spreading disease to their families. Which means toward peers grand parents.

Those children's grandparents are at risk, are you saying it is ok to cause 2nd and 3rd order infections?

So a paper has quoted 0 deaths for under 10 year olds, and you interpret that to mean that children are immune?

Planes crash, the Airbus A380 has suffered 0 crashes, so would you interpret this to mean the A380 cannot crash?

I think a problem with this analogy is you are comparing children not dying from a disease they do have to an airplane which doesn't have the problem you mention.

Lets square up the analogy. So there are 0 deaths for children that get coronavirus, and about 1/5 of the cases have been among children.

Planes crash, and out of all the planes that have crashed about 1/5 of the passengers were children, if 0 of the children died would you interpret this to mean children can't die in plane crashes?

And yes, basically I would interpret it that way if it were true.

Ok, maybe I can make it closer to your analogy:

There were 0 deaths for children that get caronavirus, maybe you think children are much less likely than adults to die if infected? Planes crash, if the A380 has never crashed despite millions and millions of miles in service, would you interpret that to mean that an A380 is much less likely to crash than other plane models that have flown a similar number of miles and had a bunch of crashes?

Again, yes, that is just how statistics work.