Vaccination is the administration of a vaccine and is used to stimulate the immune response of a person in order to develop immunity towards a pathogen.
Vaccines are harmless mutants of a pathogen or related, but non-pathogenic strains of a pathogen. Small fragments of a pathogen are also often suitable for use as vaccines. Vaccines induce an immune response towards the vaccine itself, as well as towards the pathogen they represent. Therefore, vaccination leads to immunity.
A measure of being alive and vivid.
A virus is a small infectious agent that requires living cells to divide and propagate. Viruses infect all types of organisms – animals, plants and bacteria – although every virus is highly specific for its own host organism.