Decreased Humoral Immunity to Mumps Seen in Young Adults
WEDNESDAY, Sept. 4, 2019 -- The frequency of circulating memory B cells (MBCs) specific for mumps is much lower than that of those specific for measles and rubella among healthy college-aged students who were vaccinated in childhood, according to a study published online Sept. 2 in the Proceedings of the National Academy of Sciences.
Following multiple mumps outbreaks, with high attack rates among young adults, Mohammed Ata Ur Rasheed, Ph.D., from the Emory University School of Medicine in Atlanta, and colleagues assayed blood samples from 71 healthy 18- to 23-year-old college students living in a nonoutbreak area for antibodies and MBCs to mumps, measles, and rubella. Almost all of the participants (69 of 71) had received two doses of the measles-mumps-rubella vaccine in childhood.
The researchers found seroprevalence rates of 93, 93, and 100 percent for mumps, measles, and rubella, respectively, as determined by immunoglobulin G (IgG) enzyme-linked immunosorbent assay. The concentration of IgG was significantly lower for mumps than rubella. In sera of 59 of 71 participants who had sufficient IgG levels, high IgG avidity to mumps Enders strain was detected. Compared with measles and rubella, the frequency of circulating mumps-specific MBCs was five to 10 times lower; 10 percent of participants had no detectable mumps-specific MBCs. Geometric mean neutralizing antibody titers to the predominant circulating wild-type mumps strain (genotype G) were sixfold lower than those against genotype A (the Jeryl Lynn vaccine strain).
"Strategies to improve the longevity and quality of the humoral immune responses to the current mumps vaccine need consideration," the authors write.
Merck provided mumps vaccine strains for the MBC assays and provided funding to Emory University.
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Posted: September 2019