There is a surgical practice of medicine and there is a medical practice of medicine. Medicines are poisons which when taken in a small amount help you get the benefit of the poison. Taken in a larger amount, all medicines can kill you. Also, medicines have a purpose and a use along with interactions with other chemicals in your blood and many medicines need proper organ function else you get overdosed - example your kidneys need to be working well for you to be able to pee out certain antibiotics like Levaquin. Else the levels will build up and cause toxicity or poisoning.
Herd immunity is a form of immunity that occurs when the vaccination of a significant portion of a population (or herd) provides a measure of protection for individuals who have not developed immunity
