Did you see the Pfizer RNA gen therapy induced CoV-19 cases among younger 10..29 in Israel. Factors more vaccinated young in hospital compared to unvaccinated...
If you consider your own argument - that children with known risk factors are much more likely to suffer form COVID than others - this is explained. You can see that for 12-15 age range - with a very small number of children - vaccinated and unvaccinated are about level per 100K. That is much worse than for higher ages.
- Anyone with an at-risk child would get them vaccinated
- Most of the hospitalisation would be driven by at-risk children
- Therefore more vaccinated in hospital.
This is a general confounder that tends to make vaccination hospitalisation or death rates look worse than they really are. Any known risk factors are positively correlated with vaccination - so unless you can control for them they represent powerful confounders. But it will particularly affect young ages where COVID risks are much lower and children with strong co-morbidities - e,g, immunocompromised will be in regular contact with hospitals, and will be very strongly advised to get vaccinated.
You know that of course - therefore I'd appreciate it if you indicated to others who maybe are not as used to thinking about this typemof maths as you are that this is an issue.
THH