A vaccine is a biological product that is produced by weakening, inactivating, or genetically engineering pathogenic microorganisms or their metabolic products. It is used to prevent infectious diseases and other diseases such as cancer. Currently, vaccines have become an important weapon in the global fight against the COVID-19 pandemic. Vaccines produced through different technological routes have their own advantages and disadvantages. For example, inactivated vaccines have the advantages of mature production processes and strong antigenicity, but they also have disadvantages such as high production costs, slow production speed, short immune period, and the need for multiple immunizations. Viral vector vaccines do not require the cultivation of infectious viruses, have higher safety, induce cellular immunity, and have better immune effects, but they may face the challenge of pre-existing immunity. Compared with traditional viral vaccines, mRNA vaccines deliver the mRNA of key viral proteins into the body through delivery carriers, and have significant advantages over the previous two generations of viral vaccines.