The measles vaccine (MMR) is generally not recommended for infants under 12 months of age. This is because maternal antibodies, transferred during pregnancy, can interfere with the vaccine's effectiveness against measles in younger infants. However, in epidemic situations, the measles vaccine may be administered from 6 months of age. It is important to note that doses given before 12 months are considered early doses and do not replace the routine vaccinations required at 12 months and between 4-6 years of age.