It's so surreal, because we've watched this one evolve in real time. Anti-vax was not a mainstream conservative position even five years ago. You were much more likely to hear it from progressives, as an anti-corporate and anti-big-pharma position.
I think that's where RFK Jr. started from. He was rejected by progressives, and eventually conservatives welcomed him.
In just five years we went from "COVID is not a problem" to "We don't need a COVID vaccine" to "The new COVID vaccine must be bad" to "all vaccines are bad". It didn't even take five years; it was really set by 2022.
It was never a conservative goal before that, and you were much more likely to hear conservatives pretend that it was a mainstream liberal position by highlighting the small number of celebrity dimwits. Surely somebody is out recruiting Jenny McCarthy for CPAC.