Yeah, I can't say for sure of course, but I think a lot of the vaccine scrambling is a "sheet just got real" response. It's easy to have a position against vaccination (whether for religious, political, or even just basic anxiety reasons) when it's just an idea and possible risk. But when the risk becomes very real, people react differently and scramble to do it.
I think it's an unfortunate reality we live in these days - many (not all) people don't see the reason for protecting against something unless and until it becomes an immediate threat in their lives.