My question is not a duplicate, for reasons that I have explained within the question itself. Can it please be re-opened?
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I suggest you have a read of the Welcome to New Users FAQ.
Your question has been substantially rewritten to make it possible to re-open it.
In particular, the irrelevant references that were distracting from the claim have been removed and the relevant references have had their key claims cited.
I think it remains a poor question. The answer to the question is clearly explained in the articles provided: There is some evidence that face shields work. There is not yet evidence that they are as effective as face masks. The CDC is not saying "Face shields have been shown to be ineffective", they are saying "face masks have been shown to be effective, and face shields haven't got enough evidence, so we recommend face masks".
Because the answer has already been provided in the question, it will be difficult to answer. (What is there to add?)