Comment by chiefalchemist

Not really. They used the cutoff date to develop a theory. That is, those before the date couldn't get the vax vs those after the date that did.

So far, so good.

However, not everyone after the date got the vax. That is, like tge before date "control" there are a post-date group who also did not get the vax. Oddly, there's no mention how this group fared.

Obviously, they know this group exist. And that the initial theory would be ideal to apply to this group. That didn't happen.

That would be definite. As it is, a key and obvious piece is missing.