Yes they do need it
Yes all babies, children
, adults need vitamins and most get it in their diets
and for babies on breast milk or formula
feedings they get all the vitamins they need in first 4to6 months.
The only exception is vitd which is recommended as a supplement for breast fed babies who drink less than 32oz of formula per day.Babies on solid food get enough vits.Vitd400 unt daily if breast fed babies as suplemen.