An mRNA vaccine is a type of vaccine that is composed of mRNA, which enters the body and transmits a special message to induce an immune response. Currently, mRNA vaccines developed in the clinical stage target diseases such as HIV, influenza virus and rabies virus. mRNA is a very important substance in the process of protein expression. mRNA is a kind of genetic material that can transmit instructions to the organism, so that the organism can utilize its own material to express specific proteins and play specific roles. The principle of mRNA vaccine is to make a vaccine from the genetic material that can express specific proteins. The vaccine can stimulate the body to synthesize specific proteins after entering the body, and the synthesized proteins are equivalent to antigenic substances that enter the body, which can stimulate the immune system of the body to produce immune responses and then produce corresponding antibodies to prevent pathogens from re-infecting the body. Please consult your physician for more information about vaccination and precautions.