An mRNA vaccine has never been mass-produced and licensed to treat an infectious disease. The mRNA vaccines to treat the novel coronavirus would be the first. ... The biotechnology giants Moderna and Pfizer/BioNTech announced [November 2020] that they had seen promising results as they near the end of clinical trials for their vaccine candidates. Both vaccines are likely to be produced on a wide scale and distributed en masse to the public. Yet what is particularly striking is that both are mRNA vaccines, mRNA being short for “synthetic messenger RNA.” Understanding why these are so novel requires some background on the history of vaccination. ... “Live-attenuated vaccines are often very effective but they sometimes induce adverse events” ... Another related subtype of vaccines are called protein subunit vaccines... Viral vector-based vaccines, and genetic vaccines like those which use DNA and RNA, are the second and third main vaccine technologies. “When you use viral-vectoredbased or genetic vaccines, you deliver a blueprint that will allow the host cells to produce protein antigens that will then induce an immune response” ... you’re giving the cells a blueprint rather than a piece of the pathogen itself …

You can read more about this on the AIU Campus Mundi January 2021 Magazine