I was also a bit shocked when I saw how high the Personal Belief Exemption was in some counties. Above 5% unvaccinated pretty much destroys herd immunity. So most of northern California is a no-go zone for people who appreciate the value of herd immunity.
What I have not seen, but would like to, is data for other states.
Fortunately, the highest-population counties in northern California are not too high - the number of schoolchildren in such counties is much lower that this map would indicate.
What I have not seen, but would like to, is data for other states.