Not a virologist, but I've heard of viruses in the past that mutated into asymptomatic variants, which are then basically contagious vaccines. Artificially cre

Not a virologist, but I've heard of viruses in the past that mutated into asymptomatic variants, which are then basically contagious vaccines. Artificially creating such a thing has been discussed, but I don't think anyone's ready to go there for ethical reasons. What if they screw it up? Also, you still need _some_ symptoms to get people to sneeze the "vaccine" to their neighbors. It's a very fine line to tread.