According to this Sep 2020 article on reason.com (1) they quote CDC numbers of a 99.98 survival rate (0.02% IFR) for 20-to-49-year-olds. Or a 99.997% survival rate (0.003 IFR) percent among people 19 or less.
1: https://www.google.com/amp/s/reason.com/2020/09/29/the-lates...