Portal:Medicine/Selected article/3, 2008
Vaccination is the administration of antigenic material to produce immunity to a disease. Vaccines can prevent or ameliorate the effects of infection by a pathogen. The material administrated can either be live, but weakened forms of pathogens such as bacteria or viruses, killed or inactivated forms of these pathogens, or purified material such as proteins. Smallpox was the first disease people tried to prevent by purposely inoculating themselves with other types of infections; smallpox inoculation was started in India or China before 200 BC. In 1718, Lady Mary Wortley Montague reported that the Turks have a habit of deliberately inoculating themselves with fluid taken from mild cases of smallpox and she inoculated her own children.
(More...)