ABSTRACT
At present, Corona Virus Disease 2019 (COVID-19) caused by SARS-CoV-2 still spreads worldwide, bring great health risk and economic burden. Vaccination is an important measure to prevent and control the spread. The mRNA vaccines introduce the mRNAs encoding antigen protein into human body and translate directly to form the corresponding antigen protein thus induce specific immune response. As one of the nucleic acid vaccines of the third generation after inactivated vaccine, live attenuated vaccine, subunit vaccine and viral carrier vaccine, mRNA vaccines have characteristics of rapid response to pathogen variation, simple production process and easy scale expansion. This reviews the progress in research on immunological characteristics, molecular design, delivery system and safety as well as the relevant mechanisms.