Inoculation

Inoculation is the placement of something that will grow or reproduce, and is most commonly used in respect of the introduction of a serum, vaccine, or antigenic substance into the body of a human or animal, especially to produce or boost immunity to a specific disease. It can also be used to refer to the communication of a disease to a living organism by transferring its causative agent into the organism, the implanting of microorganisms or infectious material into a culture medium such as a brewers vat or a petri dish, or the placement of microorganisms or viruses at a site where infection is possible. The verb to inoculate is from Middle English inoculaten, which meant "to graft a scion" (a plant part to be grafted onto another plant); which in turn is from Latin inoculare, past participle inoculat-.

This article covers variolation, inoculation as a method of purposefully infecting a person with smallpox (Variola) in a controlled manner so as to minimise the severity of the infection and also to induce immunity against further infection. See vaccination for post-variolation methods of safeguarding as if by inoculation by administering weakened or dead pathogens to a healthy person or animal with the intent of conferring immunity against a targeted form of a related disease agent.

Today the terms inoculation, vaccination and immunization are used more or less interchangeably and popularly refer to the process of artificial induction of immunity against various infectious diseases. The microorganism used in an inoculation is called the inoculant or inoculum.