Serologic response to measles-mumps-rubella vaccine among children with upper respiratory tract infection.

The influence of concurrent upper respiratory tract infection (URTI) on immune response to MMR (measles, mumps, rubella) vaccine was evaluated by measuring IgG levels for each viral component immediately before vaccination and 6 months after vaccination in 198 12-month-old children (101 children without URTI and 97 with URTI at time of vaccination). None of the children had antibodies to measles, mumps or rubella before vaccination. Seroconversion rates and the geometric means of the antibody titers in children without URTI and in children with URTI at the time of vaccination were similar. MMR vaccination should not be delayed in children with such infections.