Doctors use two main types of drugs for the ___________ of disease:
Vaccines contain dead or ___________ germs. They cause the body to develop ________ called ________ that act to _________ disease. Doctors _______ ________ before a person has been exposed to such ________ as poliomyelitis or __________ . Vaccines are usually ________ but sometimes are given ________ . Serums contain antibodies that ________ off the germs of certain diseases, _______ scarlet fever and lockjaw. These drugs are given ________ a person has been exposed to the disease, or after _________ of the disease have appeared. ________ are __________ administered by injection.