The COVID-19 Real-time Learning Network provided this explanation of the history of mRNA vaccines:
"The concept of mRNA vaccines was first developed in the early 1990s (Schlake, 2012). However, due to difficulty with the instability of mRNA, delivery challenges and other factors, the field did not make significant strides until the past decade, when technological advances and investment lead to significant development. Prior to the COVID-19 pandemic, mRNA vaccines targeting infectious diseases including HIV-1, rabies, Zika, and influenza were already in clinical trials, as were mRNA vaccines targeting multiple hematologic and solid organ malignancies (Pardi, 2018)."
The COVID-19 Real-time Learning Network is brought to the frontline healthcare community by the CDC and IDSA (Infectious Diseases Society of America.).