A vaccine is a biological preparation that provides acquired immunity to a particular disease. Vaccines are made from microbes. The antigen in the vaccine is the same as the antigen on the surface of the disease-causing microbe. The vaccine stimulates the body to produce antibodies against the antigen in the vaccine. The antibodies created will be the same as those produced if the person was exposed to the pathogen. When the vaccinated person comes into contact with the disease-causing microbe, the antibodies recognize the pathogen and act against to it. Hence, the vaccine should be given before attacking of the disease.
A vaccine is a biological preparation which provides active acquired immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened (attenuated) or killed forms of the microbe, its toxins or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as a threat, destroy it and keep a record of it so that the immune system can more easily recognize and destroy any of these microorganisms that it later encounters.