mRNA vaccine is a nucleic acid vaccine, in which mRNA sequences encoding specific antigens, synthesized in vitro, are introduced into the body and expressed as corresponding antigenic proteins to prevent diseases by inducing an immune response of the immune system against this antigenic protein. mRNA vaccines are now mainly used to prevent and treat a variety of infectious diseases: 1. RNA virus infectious diseases: mRNA vaccines can be used for the prevention of highly infectious and harmful RNA virus infectious diseases, such as neo-coronavirus infection, which has already played an important role in the prevention of neo-coronavirus infection; 2. DNA virus infectious diseases: mRNA vaccines can be used for the prevention of DNA virus infectious diseases such as cytomegalovirus. Theoretically, mRNA vaccine can also be used for bacterial infectious diseases such as streptococcus and mycobacterium tuberculosis. mRNA vaccine has the advantages of high efficiency, safety and low cost, but its expression in the body is not stable enough and may cause some side effects such as local reactions or systemic reactions, so patients are recommended to be vaccinated under the guidance of doctors.