People who are susceptible to conspiracy theories are probably not going to only be susceptible to one of them. I would expect the intersection of QAnoners and anti-vaxxers to be quite large. And a lot of the evangelicals I know believe there is going to be a chip (mark of the beast) in the covid vaccine.
I wouldn’t say conspiracy theorists are naturally more drawn to GOP ideals, whatever those are these days, but I think the GOP has done a better job of appealing to them, with an embrace of conspiracy theories in general.
There are some absolutely batshit crazy conspiracy theorists among Democrats, but it doesn’t feel as mainstream to me.
So, yes, about 75% of the anti-vaxxers I know are Trump-or-die QAnoners. Before Trump, they thought Hillary was running a pedo ring.
I bet if I lived in Portland, I’d have a very different experience, though.