The Effect of Measles Vaccination Before Turning 1 Year-old on the Measles Antibody Response to Immunization with MMR

Choi, Soo Jung; Koh, Young Jae; Sohn, Young Mo; Lee, Hoan Jong; Oh, Sung Hee

Abstract

PURPOSE: With the implementation of measles vaccination programs, the number of patients with measles has decreased. However, epidemics still occur with high morbidity in infants less than 1 year of age. This fact calls for the establishment of optimal preventive measures against measles. The study was carried out to determine the effect of measles vaccination on an infant immunized before one year of age, any the measles immunity conferred by MMR.
METHODS
Seventy-seven healthy infants (13.7 +/- 1.8 months) were immunized with the MMR vaccine (Triviraten Berna : Edmonston-Zagreb strain, Rubini strain, Wistar RA 27/3 strain), 50 of the infants have received measles vaccine before turning one-year old. The antibody titers of measles-specific IgG were measured by enzyme immunoassay.
RESULTS
The antibody titers before and after MMR vaccination were significantly higher in infants previously immunized with measles vaccine compared to those not immunized. However, the greater number of infants not previously immunized with measles vaccine showed significant increase of measles antibody titers after MMR vaccination compared to those previously immunized with measles vaccine. Measles vaccine failure occurred in 6 infants (12.0%), all of whom acquired measles immunity following MMR vaccination. Measles immunogenicity to MMR did not differ with respect to the age of previous measles vaccination.
CONCLUSION
The results indicate that measles vaccination in infants less than 1 year of age will not decrease the measles immunity following MMR vaccination, and it is suitable to vaccinate against measles in infants between 6-12 months of age, if needed.