The term VACCINE MEDIUM can be summarized as a SERUM used to create vaccines. SERUM is a liquid component of blood that contains antibodies and other proteins, and it is used in the production of vaccines to provide immunity against certain diseases. Vaccines are made by introducing a weakened or killed form of a virus or bacteria into the body, which then stimulates the body's immune system to produce antibodies that protect against future infection. The use of SERUM in vaccine production helps to ensure that the vaccine is effective and safe for use.