[pianoben]

Not so; the mRNA technology used to develop and deliver the vaccine has been in progress for decades. The hardest parts were done before SARS-CoV-2 ever existed, but it's wrong to claim that "the vaccines" needed to be tweaked - they never existed.

[pclmulqdq]

For people confused about this, there were prior commercial attempts at coronavirus vaccines, with mixed success. They were not RNA vaccines. The COVID-19 vaccines built on that research (regarding what proteins to target, in particular), but the COVID vaccines that were rolled out were completely novel technology.