Inoculation

Inoculation is the act of implanting a pathogen or other microbe or virus into a person or other organism. It is a method of artificially inducing immunity against various infectious diseases. The term "inoculation" is also used more generally to refer to intentionally depositing microbes into any growth medium, as into a Petri dish used to culture the microbe, or into food ingredients for making cultured foods such as yoghurt and fermented beverages such as beer and wine. This article is primarily about the use of inoculation for producing immunity against infection. Inoculation has been used to eradicate smallpox and to markedly reduce other infectious diseases such as polio. Although the terms "inoculation", "vaccination", and "immunization" are often used interchangeably, there are important differences. Inoculation is the act of implanting a pathogen or microbe into a person or other recipient; vaccination is the act of implanting or giving someone a vaccine specifically; and immunization is the development of disease resistance that results from the immune system's response to a vaccine or natural infection. Until the early 1800s inoculation referred only to variolation (from the Latin word variola = smallpox), the predecessor to the smallpox vaccine. The smallpox vaccine, introduced by Edward Jenner in 1796, was called cowpox inoculation or vaccine inoculation (from Latin vacca = cow). Smallpox inoculation continued to be called variolation, whereas cowpox inoculation was called vaccination (from Jenner's term variolae vaccinae = smallpox of the cow). Louis Pasteur proposed in 1861 to extend the terms vaccine and vaccination to include the new protective procedures being developed. Immunization refers to the use of vaccines as well as the use of antitoxin, which contains pre-formed antibodies such as to diphtheria or tetanus exotoxins. In nontechnical usage inoculation is now more or less synonymous with protective injections and other methods of immunization. Inoculation also has a specific meaning for procedures done in vitro (in glass, i.