A few things
The virus doesn't cause the fever, your body does, and that's a good thing. Fever should only be treated for specific reasons.
Also, the availability of steroids and antibiotics absolutely reduces fatality rates. Antibiotics reduce secondary infections.
This is a novel Corona virus, meaning it's brand new, but there are lots.of other Corona viruses, many of them cause common colds. This could be a reason why children seem to be less effected
The annual fatality rate of influenza is not 0.1 percent, it's around 0.01 percent or less. The Spanish flu had a fatality rate of over 2 percent.
https://jamanetwork.com/journals/jam...rticle/2762130
This JAMA article article estimates the china fatality rate at 2.3 percent, but this is likely not complete data