The vaccine industry recognized the potential of mRNA vaccines as far back as the 1980s.1 It anticipated that mRNA molecules could be synthesized in large quantities more quickly and cheaply than proteins.2 And it also knew that mRNA vaccines would help patients avoid infection risks of the sort posed by live attenuated viral vaccines. Eventually, experimental mRNA vaccines advanced to preclinical studies. For example, mRNA vaccines were evaluated in animal models of rabies,3 influenza,4 Ebola, and Zika.5 Until recently, however, challenges associated with delivery and stability hindered development.
