A video has surfaced of Meta, then Facebook, that was recorded at a virtual Q&A meeting for Facebook staff that was streamed live on July 16, 2020.
In the video Zuckerberg states:
"I do just want to make sure that I share some caution on this because we just don't know the long-term side effects of basically modifying people's DNA and RNA to directly code in a person's DNA and RNA.
Basically the ability to produce those antibodies and whether that causes other mutations or other risks downstream. So there's work on both paths of vaccine development."
That was fine for Zuckerberg's people, but Facebook went on at that time to supress much vaccine criticism along the same lines. Later Zuckerberg did admit to such censorship, but claimed that the Biden administration forced him to, much a schoolboys caught in mischief often say. As I see it, it would not have taken much pressure for Facebook to have censored, as it was in line with their mode of operation then, maybe still is.
https://www.thefocalpoints.com/p/we-dont-know-the-long-term-side-effects