How are vaccines designed to work?
The actual immune mechanism by which vaccines stimulate immunity in a vaccinated animal depends on many things including the nature of the disease causing organism (bacteria vs virus for instance), the state of the organism in the vaccine (live, weakened, dead), the part of the organism used to make the vaccine (whole, part, recombinant), the vaccine carrier (adjuvants, viruses, chemical vehicles) and how the vaccine is delivered (oral, aerosol, injectable). Whatever the makeup of the vaccine and the type of response that it stimulates in the animal, all vaccines are designed to protect the vaccinated animal against a real-life challenge from organisms found in nature. Vaccines do not protect an animal against all organisms, only those that are included in the vaccine. When vaccinated the animal is actually given a dose of the disease causing organism, but in a harmless or non disease causing state. Instead of creating disease the vaccine stimulates the animal to produce protective cel
