The New York Times published an article last year with the entire genome of the SARS-Cov-2 virus, with a breakdown of different sections to explain what protein the RNA codes for and what that protein does. Like you said it was amazing that it all fit within an [albeit long] newspaper article. It doesn't surprise me that the RNA for the vaccine, which only targets a single protein, is even smaller than that. Here's the NY Times article I was referring too:

https://www.nytimes.com/interactive/2020/04/03/science/coron...