The whole point of clinical trials is to get statically significant numbers so that you can understand if the vaccine is safe, months after administration. It was done before the vaccine was approved.
Now you can debate the meaning of "safe". And you can make decisions based on anecdotes. And you can say it would be nice to have better data. But that is true for most things in life. Most people go to restaurants and drive their cars on roads with reviewing far less evidence that their car and restaurant they are going to are truly safe.
https://www.nejm.org/doi/full/10.1056/nejmoa2034577
Now you can debate the meaning of "safe". And you can make decisions based on anecdotes. And you can say it would be nice to have better data. But that is true for most things in life. Most people go to restaurants and drive their cars on roads with reviewing far less evidence that their car and restaurant they are going to are truly safe.