I think my answer is, depends on how effective it is. A 100% effective vaccine against confirmation bias would leave me believing whatever the last piece of evidence I read said. I’d be constantly changing my mind and never sticking with anything long enough to see results.
That said, confirmation bias also can work against you, keeping you from believing useful new things even in the face of overwhelming evidence. Confirmation bias is exactly what keeps mainstream myopes and optometrists from joining us here. (Although it also keeps us here after visiting our mainstream optometrist.)
So what is the right amount of confirmation bias? Would different people need different doses of this vaccine? (Assuming somewhat linear dose-response relationship.) Would some lives be ruined by this vaccine?
Tangentially related: Not a cult? (more rituals needed please)