Reimmunization following early immunization with measles vaccine: a prospective study.

A prospective study was designed to determine the response of previously immunized infants following administration of measles vaccine at 15 to 18 months of age. Upon entry into the study at 7 to 12 months of age, 14 of 127 infants had measles antibody. Measles vaccine was administered to infants in the experimental group on the day of entry into the study. Prior to measles, mumps, and rubella vaccine administration at 15 to 18 months of age, six of 23 infants in the control group and 80 of 90 infants in the experimental group had detectable antibodies. Following the (re)vaccination at 15 to 18 months of age, 20 of 21 infants in the control group and 49 of 52 infants in the experimental group had detectable antibody. Early measles immunization in this study did not interfere with the ultimate response to immunization at 15 to 18 months of age. These results support the policy of early immunization for those infants at risk for exposure to measles and reimmunization at 15 months of age.