It’s a strange global phenomenon and I don’t think there is one single root cause. MAGA/MAHA definitely jumped on to the anti-vax train as it became popular, but many forget that Trump presided over the rushing of the COVID vaccine into availability and production. He hasn’t done vaccination any favors in recent years, but I’m skeptical that the widespread rise of vaccine skepticism can be attributable to this administration alone.
I think there’s a bigger story about the cyclical nature of how the dangers of threats that previous generations faced is slowly lost over time, combined with the rise of contrarianism and conspiratorial thinking on social media.