>"Fascinating--do you have any links to further reading/watching about this?"

https://www.nature.com/articles/nrd.2017.243

The basic idea is that now rather than needing to culture live viruses in chicken eggs, we can literally just encode the RNA for a specific antigen into a synthetic substrate and produce vaccines through a chemical process like any other drug. The RNA is then absorbed into your cells, and your own body creates the proteins which stimulate an immune response.