I would study the whole area of the effectiveness of immunisation before letting them be immunised.
Compulsory ones nowadays seem to autism/ADH/epileptic fits and ritalin, oh, sorry that last one was the end product they sell to deal with the effects of vaccines..
If you must have your kids shot, chose a private doctor and give them the vacs individually over a period, as long as you can manage, do not allow vaccination whilst they have even a head cold, nothing if they have anything worse, and ask your doctor to find non mercury vaccines, they may be OK, or they may be unfortunate and get one of those manufactured diseases that seem to occur since we started mandatory vaccinations.
Not sure whether they disburse them randomly amongst the vaccine stock, or it's just a combination of lowered immunity attacked by viral infections designed to provoke the reaction.
I resorted to Photoshop to protect my kids, though they got one of them with a triple shot when I was not aware, and she suffered epilepsy for five years before we cleaned out the toxins and mercury from her body, apart from that they grew up fine and healthy sans vaccines.