Common types of vaccines are live attenuated vaccines, whole inactivated vaccines, subunit vaccines and toxoid vaccines. Up to now, along with advances in recombinant DNA technology, genomics, virology and molecular immunology, they have had a great impact, opening up application directions in the production of new generation vaccines. Many vaccine design strategies have been studied and applied in the process of preventing and treating infectious diseases, in which DNA vaccines have shown to have promising prospects in new generation vaccines.

The principle of using vaccines is to introduce into the body antigens derived from pathogenic microorganisms or microorganisms with antigenic structures similar to pathogenic microorganisms, which have been prepared to ensure the necessary safety, causing the body to create its own immune state against the pathogen (ie, to induce artificial active immunity). The four common types of vaccines are live attenuated vaccines, whole inactivated vaccines, subunit vaccines and toxoid vaccines.