Durability of the Mumps Antibody Response After the Third Dose of MMR Vaccine

Area of Science:

• Immunology
• Vaccinology
• Public Health

Background:

• Limited data exists on the long-term immunogenicity of the mumps component of the measles, mumps, and rubella vaccine (MMR).
• The third dose of MMR (MMR3) is used in various settings, necessitating understanding of its durability.

Purpose of the Study:

• To investigate the durability of mumps antibody responses up to 11 years after a third dose of the MMR vaccine (MMR3) in adults.
• To assess long-term susceptibility to mumps infection following MMR3.

Main Methods:

• Adults vaccinated with MMR3 between ages 18-28 years had sera collected at multiple time points up to 11 years post-vaccination.
• Mumps antibodies were measured using plaque reduction neutralization assays (against vaccine and wild-type strains) and immunoassay (EIA).
• Susceptibility was defined by low antibody titers (Genotype A <31, Genotype G <8) or low EIA index (<1.10).

Main Results:

• Susceptibility to mumps based on vaccine strain (Genotype A) antibody titers increased significantly from 15.7% at baseline to 30.5% at 9-11 years post-MMR3.
• Proportion of participants seronegative for mumps IgG by EIA rose from 0% at baseline to 7.5% at 9-11 years.
• Antibody titers against the wild-type mumps strain (Genotype G) were consistently lower than those against the vaccine strain.

Conclusions:

• A substantial proportion of adults exhibit antibody levels predicting susceptibility to mumps infection 9-11 years after receiving a third MMR dose.
• The waning antibody levels suggest potential challenges in maintaining long-term population immunity against mumps.
• Lower antibody responses to wild-type mumps strains compared to the vaccine strain warrant further investigation.