Not sure where you are getting your numbers, but they are way off. Here are the number for flu deaths from the CDC
0-4 years 1.3%
5-17 years 0.4%
18 - 49 years 1.8%
50 - 64 years 9%
65+ years 48.7%
Maybe Scientific America should fact check with the CDC.
https://www.cdc.gov/flu/about/burden/2018-2019.html