One interesting feature of the data in the paper is that the level of vaccine hesitancy in more educated people seems to have been much flatter over time than that of less educated people [0]. It's as if more educated people were more likely to have made up their minds from the start. Unfortunately, I don't think the paper provides any information on how training in different academic subjects correlates with vaccine hesitancy—a PhD can be in molecular biology just as much as it can be in comparative linguistics.
[0] Page 27: https://www.medrxiv.org/content/10.1101/2021.07.20.21260795v...