This is a really interesting point I haven't thought of, but haven't we really already reached that point? Terrible diseases that used to wipe out entire civili

This is a really interesting point I haven't thought of, but haven't we really already reached that point? Terrible diseases that used to wipe out entire civilizations are stopped dead (heh) in their tracks by taking a pill for a few weeks, stopping us from developing an immune system that can respond well.