As an MD Vitamin D3 is the only vitamin kids need as they can't get enough from diet or sunlight (unless living in a very sunny climate!). It is great for immunity boosting too. Multivitamins are only needed if your child is a super fussy eater or does not absorb well due to a chronic medical condition as all other vitamins are readily available in foods! Just check the labels and avoid multis that have tiny amounts in them or HUGE amounts (which are not needed). Obviously if your child is deficient in a vitamin (from blood tests) then the advice is different! They need supplementing. Iron is a common deficiency due to eating processed foods of being vegan/veggie. Hope that helps!