Current estimate is that some 5.6 billion people took at least one dose of a COVID vaccine[0]. You would think that if there severe complications, we would have seen them in, I don't know, hundreds of millions of people by now. Any day now, I am sure those people will all get super cancer and/or turn into zombies.

[0] https://ourworldindata.org/grapher/people-vaccinated-covid?c...