How do vaccines interact with the body?
Live viruses, e.g. a live vaccine against poliomyelitis (“polio vaccine”), smallpox vaccine, etc., are intended to multiply (replicate) in the body of the vaccinated person. Owing to the nature of viral replication, the viruses must enter the host’s cells and then be released, perhaps to infect new cells. However, as soon as they are released from the initially infected cells, the viruses stimulate the immune system to one or both types of defense. One defense uses non-living substances manufactured by the body called “antibodies” (antibody-mediated immunity). The antibodies bind to the viruses and prevent their entry into other cells. They may also assist in removing the viruses by enabling cells that swallow and digest such junk to get rid of the antibody coated viruses. The other defense (cell-mediated immunity) causes some of the host cells that specialize in such reactions to recognize cells which have become infected by a virus and kill those cells, thereby preventing them from r
