I can’t speak for anti-vaxxers or covid-deniers, but I have a friend who refuses to get the covid vaccine because she’s genuinely scared of blood clots. (Please don’t come at me with reasons why this is stupid, I know, I’ve tried, I think she has a legit irrational phobia that cannot be rationalised away:/) I would imagine a lot of people who aren’t good at/interested in looking deeper into the vaccines genuinely fear that there are side-effects we don’t know about or that are being downplayed. Like my friend uses that fact that one doctor in Finland said it’s unethical it’s not injected using aspiration as proof that the procedure was rushed.

Ie. it’s just fear of what they perceive to be the unknown. Taking your shoes off at the airport isn’t gonna harm you, but they think the vaccine might, and if they’re healthy and young, they’ve decided their chances of getting covid in a serious way is so low they’d rather not ”risk” it.