Vaccination is the process of administering weakened or dead pathogens called vaccine to a healthy person, with the intent of conferring immunity against a targeted form of a related disease agent.
The term was coined by Edward Jenner and adapted by Louis Pasteur for his pioneering work in vaccination. Vaccination (Latin: vacca—cow) is so named because the first vaccine was derived from a virus affecting cows: the cowpox virus, a relatively benign virus that provides a degree of immunity to smallpox, a contagious and deadly disease. In common speech, 'vaccination' and 'immunization' generally have the same colloquial meaning. Vaccination efforts were initially met with some resistance before early success brought widespread acceptance and mass vaccination campaigns were undertaken.
The eradication of smallpox, which was last seen in a natural case in 1977, is considered the most spectacular success of vaccination. Some people assert that childhood vaccination plays a role in autoimmune disease and autism, though large-scale scientific studies have not shown any link.
See also immunization