[ben_w]

While any sane person would agree in general, it isn't hard to find examples of experts in any domain who made some mistake in that domain at some point.

Also, normal people are absolutely terrible about probability.

Combined, I therefore suspect it's "I know they're normally right, but not about this."

[korm]

In this case it's not disagreement with one expert, or even a few. The vaccination schedule is based on a consensus of experts. Not only across organizations, like the CDC, AAP, FDA, but across nations too, more or less.

It's truly bizarre to _radically_ disagree, especially as a layperson.

[ben_w]

I mostly share your assessment, except that I think the word "bizarre" presumes how normal people behave. These kinds of attitudes have been around since at least the Spanish Flu pandemic, so it's important to… how do I phrase this? To account for such attitudes when planning public health campaigns, and not just dismiss such people as arrogant fools with no self-awareness.