Don't confuse "I don't hear about it in my daily news for the general public" for "nobody has considered it". You are not receiving an unfiltered medical-profes

Don't confuse "I don't hear about it in my daily news for the general public" for "nobody has considered it". You are not receiving an unfiltered medical-professional-level summary of all efforts currently underway. You're receiving a chaotically chosen, filtered-through-reporters (who mostly don't understand any of this beyond the middle-school level) subset of the news, further skewed by PR people actively trying to promote their own stuff. There could be any number of complicated biochemical reasons why this approach won't work on this particular virus.