Is the vaccine itself an antigen or an antigen produced after injection into the human body? Is the vaccine generally the nucleic acid of the virus? (Or a protein shell? )

Vaccine itself is an antigen, and its principle is to make the body produce antibodies by injecting a small amount of antigen, and these antibodies are stored in the body, so as to achieve the effect of preventing the antigen in a certain period of time.

Vaccines are generally protein shells of viruses, and only opal shells can be recognized and specifically bound by the body.