The role of vaccinations is to bring in a pathogen example virus, bacteria to the immune system so that it can build up immunity to the pathogen without having to have the disease. This chemical is injected into the body to get the immune system to recognize a portion of pathogen virus. In normal circumstance, most pathogens enter a person through the nose or mouth. In most vaccinations, the pathogen enters through an injection, completely bypassing the normal occupations of the immune system's defence. This would not be a major problem if the injection contained simply a killed or inactivated pathogen, as this would not pose a threat. However, since the pathogens are not a threat to cause an immune system reaction, vaccines contain something
