I think you meant to say Flu vaccine... wouldn't want you to be in trouble with the Ministry of Truth.
The CDC had to change the definition during the Covid pandemic to get people to take the shot.
New definition:
Vaccine: A preparation that is used to stimulate the body’s immune response against diseases. Vaccines are usually administered through needle injections, but some can be administered by mouth or sprayed into the nose.
(https://www.cdc.gov/vaccines/vac-gen/imz-basics.htm)
The CDC had to change the definition during the Covid pandemic to get people to take the shot.
New definition: Vaccine: A preparation that is used to stimulate the body’s immune response against diseases. Vaccines are usually administered through needle injections, but some can be administered by mouth or sprayed into the nose. (https://www.cdc.gov/vaccines/vac-gen/imz-basics.htm)