Right, but the word "prevented" in this is way too subtle and nuanced:
> whether people believed that the COVID vaccine prevented transmission of the virus
Because the correct answer is "no, it didn't prevent transmission". It likely reduced transmission. Someone who'd been vaccinated twice and still caught the virus twice would very rightly say "no, this vaccine did not prevent me from being infected"
It's a disingenuous trick question though, specifically because of the nuance that most people won't think too much about. Did the vaccine "prevent transmission"? No, obviously not. Did it seriously curb the virus from ripping through seniors care homes and killing a bunch of people? Yes.
It's the kind of question that's phrased as a gotcha, not one that actually gets insight into population beliefs and behaviours beyond "oh look they fell for my trick"
I don't think it is a disingenous trick question, I think it is a good one because it exactly matches the misinformation being spread by some antiscientific liars who repeated it without any of that "nuance" you are talking about.
> whether people believed that the COVID vaccine prevented transmission of the virus
Because the correct answer is "no, it didn't prevent transmission". It likely reduced transmission. Someone who'd been vaccinated twice and still caught the virus twice would very rightly say "no, this vaccine did not prevent me from being infected"