Vaccines

Vaccination is the process in which substances called antigens are introduced artificially into the body to stimulate the immune system, the set of cells that protects the body against infections. Those antigens are generally infectious agents – pathogens – that have been inactivated by heat or chemical treatment so that they will not cause disease, or they can also be purified proteins from the pathogens. Exposing the body to antigens leads to the production of molecules specifically directed against them, called antibodies. Antibodies create a memory of a specific pathogen (“acquired immunity”) and enable a more rapid and efficient response to a real infection with an active pathogen.