Infant vitamin D supplementation helps prevent seasonal influenza and reduces symptoms and recovery time and is safe for infants. Flu vaccines are less effective overall, cause nasty side effects, and repeated flu shots blunt effectiveness over time. So why do pediatricians deny patients that refuse to immunize their children but fail to mention vitamin d supplementation to their patients? Both are recommended by the American Academy of Pediatrics, but one recommendation carries so much more weight than the other.