I feel like a more fundamental question is "Who is qualified to interpret the data?"

Then you can ask, "Of the qualified people, what were they saying at the time?" And if you care to dive deeper, "What evidence were they using to support their opinion?" and "What is the earliest that credible information arrived that should have changed their position?" and "Did their position change, when enough new evidence came in?"

Is there some better set of questions you can think of than mine?

I wouldn't consider that misinformation. At the time those statements were made it was thought the vaccine would prevent transmission. Not a medical expert, but I always thought the reason you got a vaccine was to prevent infection. Measles vaccine is somewhere near 97% effective at stopping infection. Heck, even when the vaccines for covid first came out it was big news if there was a breakthrough infection.

Fast forward to today. The general consensus is the vaccine typically prevents serious illness and death in most cases for the common variants. It doesn't do a great job preventing infection.

One of the mistakes those in charge made was never admitting something like the following when new, solid information was understood:

1) We were wrong. 2) This is something we've never seen. 3) We're learning as we go. 4) It doesn't do what we said or thought it would do, but it does this.

No one in real power ever says anything remotely like it. They speak in absolutes and it has gotten so bad they are choosing to misrepresent studies to suggest following a path they think is best versus admitting the studies just suck.

Misinformation flagging for something like covid was never going to be practical to implement as there was so much changing on a such a limited timeframe. Toss in politics and the governing structure of the USA and it was never going to work.

>... it was thought ...

And therein lies the problem. They presented it as absolute undeniable fact, but there were no definitive studies to back up their claims at the time.

Yeah, these statements have uncertainty, but they're not being discussed. It seems that uncertainty is being intentionally omitted, and discussion of it is actively fought. This seems a terrible way to maintain trust!

>At the time those statements were made it was thought the vaccine would prevent transmission

Okay. How did they come to this conclusion? We'll never know, because we're in this asymmetric war about information, where dunking on your political enemies is more important than just being transparent. Showing us how they came to that conclusion, and then going through your points 1-4 would go a long way to restoring that trust (partially), but alas they won't do it.

Wow. I haven't kept up with pro-vaccine media (I got mine, seemed like a good idea, just haven't paid attention to the messaging very much aside from health official guidelines and such) but damn that's bad. No wonder BSABing this issue is so effective.

Some of that's excusable by "the best information at the time was wrong" and some of it's not even wrong but the usual thing I've seen a lot of the last couple years, where some people take a limited statement as absolute or saying more than it is and then claim the original was wrong (when it wasn't) but a good deal of that compilation appears to be indefensible.