Decreased measles antibody response after measles-mumps-rubella vaccine in infants with colds.

We examined the possibility that the common cold or afebrile upper respiratory tract infection might interfere with successful immunization in children who receive standard measles-mumps-rubella vaccine. Infants 15 to 18 months of age presenting at our well-child clinics for routine examination and immunizations were divided into two groups. Those infants with a history and physical findings of upper respiratory tract infection were compared with healthy control group infants who did not have upper respiratory tract infections, and who did not have a history of upper respiratory tract infection symptoms within the previous month. Both groups were studied for their serologic response to measles-mumps-rubella vaccination. Prevaccination serum samples were obtained prior to vaccine administration and postvaccination serum samples were obtained 6 to 8 weeks later. Measles antibody was measured in these serum samples by an indirect fluorescein-tagged antibody test. Ten (21%) of 47 infants with colds failed to develop measles antibody, while only one (2%) of 51 well infants failed to develop antibody. We conclude that infants with colds have a significant seroconversion failure rate associated with measles vaccine administration and that this may be the cause of some primary measles vaccine failures.