The technology used, called messenger RNA (mRNA) is not new. Research on it began in the early 1990s, and two diseases that are very close to COVID — SARS (severe acute respiratory syndrome) in 2003, and MERS (Middle East respiratory syndrome) in 2012 — helped bring the mRNA vaccine development to present day use.
The reason this virus is technically called SARS-COV-2 is that there was a SARS-1, the original one, and scientists had already begun work on developing a vaccine for that virus. So, when this pandemic arrived, they had already developed a lot of the science. A decade of work had been in progress.
SOURCE: https://www.bu.edu/articles/2021/myths-vs-facts-covid-19-vaccine/ (Boston University)