evidence: The breakthrough, in a nutshell and expanded upon below: Scientists had long experimented with creating vaccines that employ RNA (ribonucleic acid) to make proteins to fight viral infections, as opposed to the standard process of creating vaccines with snippets of a virus (usually inactive or attenuated) in order to help the body subsequently recognize that virus and fight it off. The form of RNA used in the COVID-19 vaccines (called messenger RNA, or mRNA) delivers instructions for the body to make proteins. The benefit: It’s faster, easier, and less expensive to create a vaccine using RNA. The problem: It was difficult to get RNA into a cell, RNA caused severe inflammation, and low levels of protein were made because the body saw it as an alien substance and attacked it. Weissman and Karikó used synthetic RNA that the body’s immune system doesn’t recognize, and encased the RNA in lipid nanoparticles (fat bubbles) that easily slip into cells. [...] You’ve said that research on the potential of using RNA in vaccines was growing before COVID-19. [By 2017, according to an analysis in Nature, human trials were underway to test mRNA vaccines against HIV, influenza, Zika, and rabies.] Then came the pandemic. The urgency to combat the disease drove governments, foundations, and corporations to pour money into experimental vaccine research and development, including RNA.