They haven't found original antigenic sin so far. There's a couple links with some data (although I couldn't find a pre-print or published article right now) in this comment: https://news.ycombinator.com/item?id=29005187
Side note: I hope we can do better than taking at face value investor press releases by the biopharma corps producing the vaccines.
You are correct that it isn't proving vaccine efficacy, but it is showing a different set of antibodies created by the variant vaccines that are more effective at neutralizing the targeted variant than the antibody collection created by the original, WT-targeted vaccine.
>Side note: I hope we can do better than taking at face value investor press releases by the biopharma corps producing the vaccines.
I hate science by press release too. I wish I was better at bookmarking the pre-prints and journal articles I find/read, but they'd just be a mess I couldn't find anything in either :|