[kennywinker]

> initially it was thought that they provided longterm immunity

I don't remember that ever being said. Initially it was HOPED that it might provide longterm immunity - but the vaccines were launched into a world where we still didn't have a conclusive answer to the question "can you get covid twice". If anybody was saying that, they were speaking beyond their knowledge.

As for the unexpected drop in efficacy, that is at least in part due to the fact that the covid-19 we're exposed to today is not the same covid-19 that the vaccine was targeted against.

For the record, I agree with your overall point - mRNA vaccines were not and are not a well understood system with no potential for unknown effects. But neither is covid and given the two unknowns, the vaccine seems the safer choice.