How do vaccines work if the pathogen in them is dead? A. The immune system holds on to the dead pathogen from the vaccine, and if you are infected again, the new pathogen recognizes the dead form of itself and becomes inactive so that it is not killed as well.
B. It causes memory cells to be generated so that next time the pathogen is encountered the immune response is very fast, killing the pathogen before it can do any harm.
C. The vaccine alters your body chemistry so that whichever pathogen you are vaccinated against cannot even enter your body in the first place.
D. It causes antibodies to be generated that take the form of the pathogen, so the next time it is encountered, the antibodies make the pathogen think the body is friendly and not a target.