Sickness is common but I also think same that if children do not interact with germs, they don't developed antibodies and can't cope with illness. I also find some kids around me whose nervous system is very weak.
But I think it's all because of mail nutrition and kids when interact with germs and got illness they can't grow well and their body became weak. They required proper nutrition.
bad nutrition makes the problem far worse. The food people feed their kids these days can be trash.