These data suggest that specific immune outcomes may wane at different rates and highlight our currently incomplete understanding of protective immune responses to mumps and measles.
Richard B. Kennedy, Inna G. Ovsyannikova, Antonia Thomas, Beth R. Larrabee, Steven Rubin, Gregory A. Poland, Vaccine, Volume 37, Issue 13, 22 March 2019, Pages 1775-1784
The development and wide-spread use of mumps vaccine resulted in a dramatic and sustained decrease in the incidence of mumps disease; however, since 2000, an increase in the size and number of mumps outbreaks in the United States and other countries has sparked renewed interest in the durability of mumps-specific immunity elicited by mumps vaccination. The most likely explanation for mumps cases in previously immunized persons may be secondary vaccine failure, or waning immunity. Researchers examined changes in markers of measles and mumps immunity at two timepoints, approximately 7 and 17 years after two-dose MMR-II® vaccination, and found that the mumps IgG titers exhibited a large and significant decline during this time period. There was a similar discrepancy with measles-specific immune responses.