The thing is, in the PDF that was linked shows that majority of the cases are among the vaccinated. I know the percentage of population vaccinated plays a factor in the numbers but those high numbers are still in place.
That being said, those who regularly take their kids to the pediatrician would have an idea of any issues that could possibly be in place. Also, just as adults, those who are overweight have a higher propensity for those issues. It wouldn't be impossible and the fact is, the ones that are solely against vaccines or taking their kids to the doctor wouldn't be interested in vaccinating the kids anyway.
You speak of collateral damage but how do you view the 18 and under group that will have adverse effects (and already have) based on widespread vaccination of children?