These aren't really good comparatives. That said, a good comparative is the flu vaccine, which has similar lineage/laddering structures, and a showing that the rapid laddering of covid makes it pretty much impossible to create a vaccine for solely because it mutates faster than the supply chain can generate, produce, ship, and deploy a vaccine.

I say this as someone who was regretfully part of this supply chain during the first 90 days. Bully on me for believing the $cience. God forgive me.