"The fact that the safety signals "went away" in this trial is likely more indicative of the baseline risk of the population than any change in the vaccine itse

"The fact that the safety signals "went away" in this trial is likely more indicative of the baseline risk of the population than any change in the vaccine itself" - or just the fact that sometimes, a study can give the wrong signal, the same way it can happen you land a coin three times heads in a row and yet the coin isn't biased...