Dynamics of the Antibody Response After a Third Dose of Measles-Mumps-Rubella Vaccine Indicate a Slower Decline Compared With a Second Dose

Background. Breakthrough infections of measles and mumps have raised concerns about the duration of vaccine-induced immunity, which might be improved by a third dose of measles-mumps-rubella vaccine (MMR3). Methods. Here we compared (IgG) antibody levels against measles, mumps, and rubella in blood samples of 9-year-old children and young adults (18-25 years) following MMR2 and MMR3, respectively. Results. We found that, in addition to antibody boosting for all 3 vaccine components, MMR3 resulted in lower antibody decay rates than MMR2; the declines were most prominent for mumps and rubella. Conclusions. This study suggests that MMR3 provides long-lasting seroprotection against measles, mumps, and rubella.