Inoculation is a medical procedure that involves introducing a weakened or dead form of a virus or bacteria into the body to stimulate an immune response. It is commonly referred to as an INJECTION, SHOT, VACCINE, VACCINATION, or booster SHOT. Injections are the most common form of inoculation, where a needle is used to introduce the virus or bacteria into the body. Vaccines are a type of inoculation that use a weakened or dead form of the virus or bacteria to stimulate an immune response. Vaccinations are a series of injections that are given over a period of time to ensure immunity. Booster shots are additional doses of a VACCINE that are given to maintain immunity.