No, illegal children didn’t get vaccinated in Mexico. The proportion of illegal children in California schools is much higher than 7 years ago.
It doesn’t say illegals are convincing American citizens not to get their kids vaccinated. There is a huge anti-vaccine (for anything) movement in this country that has nothing to do with illegals. And that movement is winning.
A few good epidemics and the number of unvaccinated children will be reduced by the laws of nature.