I cannot fathom how your link could possibly support your contention that 0-4 and 5-17 are "definitely" a 99.99% survival rate (IFR of 0.01% or 1 fatality out of every 10,000 infections). I suspect you are misreading the table? Care to elaborate?
Taking the data from the linked table for say 35-44 year olds is 1,798 deaths out of ~43 million population bracket, excluding influenza cases. That’s a 99.9956% survival rate. Taking all covid-19 and influenza it’s still a 99.9903% survival rate.
