Yeah, the mRNA vaccines that appeared during the last years were also only made possible after some very significant issues were ironed out. To quote from https

Yeah, the mRNA vaccines that appeared during the last years were also only made possible after some very significant issues were ironed out. To quote from https://en.wikipedia.org/wiki/Katalin_Karik%C3%B3 https://en.wikipedia.org/wiki/Katalin_Karik%C3%B3: > Before 2005, a major problem with the proposed therapeutic use of mRNA was that in vivo use led to inflammatory reactions. A key insight came about when Karikó focused on why transfer RNA (tRNA), used as a control in an experiment, did not provoke the same immune reaction as mRNA. [...] Karikó and Weissman determined how specific nucleoside modifications in mRNA led to a reduced immune response: by replacing uridine with pseudouridine. > Another important achievement by the researchers was the development of a delivery technique to package the mRNA in lipid nanoparticles, a novel pharmaceutical drug delivery system for mRNA. The mRNA is injected into tiny fat droplets (lipid nanoparticles) which protect the fragile molecule until it can reach the desired area of the body.