vaccine is used to produce immunity to various diseases. vaccines can effectively prevent the infection by the pathogens like viruses, bacteria etc. most commonly used vaccines are influenza vaccine , chicken pox vaccine, hpv vaccine etc. by taking vaccines at correct time we can easily prevent the infectious diseases. simply we can say vaccine is inactivated pathogen. the term vaccine first used by Edward Jenner in 1796. vaccination is the method in which develop artificial immunity in body. immunization means stimulating the immunity power of body by using inactivated pathogens. vaccines for aids, alzhemers disease and cancer will produced  near future. louis pasteur discovered the first vaccine against rabies virus.
different types of vaccinations are used now a days.  pathogens are cultured in cultural medium and then killed by using formaldehyde, then apply to body. the second method, the living virus particles are injected into the body in very low virulence. in third method virus proteins are injected into the body.