In the report of the Nutrition Committee, American Academy of Pediatrics on the "Prophylactic Requirement and the Toxicity of Vitamin D" (Pediatrics, 31:512) the same prophylactic dose of vitamin D is recommended for children and adolescents as for infants. This seems to me unrealistic.
Before the introduction of widespread vitamin D prophylaxis, all the babies over 3 or 4 months on the infant's ward at Bellevue Hospital had rickets during the late winter and spring. The only variation was in degree. Rickets was never seen after the first year or two except for an occasional case of "renal rickets" and "coeliac rickets."