More importantly, if they got the first two shots, but refuse the 3rd, does that make them anti-vaxxers according to THH? Or suppose they get the 3rd jab, but still want Ivermectin, does that make them Republicans?
It makes them vaccine-hesitant. But in UK we have few of those. I'd expect very few to refuse 3rd jab.
If they want ivermectin it makes them either idiots, or people inclined to trust information from fringe web-sites over their own GPs and the careful and not particularly vaccine-friendly UK regulators. (I guess the second half is included in the 1st).