I don't think that herd immunity can be achieved without a vaccine. We never had herd immunity to smallpox, polio, measles, mumps, rubella, varicella, or any o

I don't think that herd immunity can be achieved without a vaccine. We never had herd immunity to smallpox, polio, measles, mumps, rubella, varicella, or any other virus until we had vaccines for those viral diseases.