I know this is going to sound dumb but... what if we research asymptomatic individuals, isolate what went right, and bottle it?
This was my approach to diet pills. Some people are skinny and can eat whatever they want and stay thin, other people are even larger framed eat the exact same things and balloon out, so it seems as though you should instead isolate what has gone right in naturally fit people.
If some people can be asymptomatic, let's figure out how to extend that (or similar) protection to everybody else, eh?