Mumps Antibody Levels Among Students Before a Mumps Outbreak: In Search of a Correlate of Immunity

Abstract

Case patients generally had lower preoutbreak mumps antibody levels than nonpatients. However, titers overlapped and no cutoff points separated all mumps case patients from all nonpatients.

Dynamics of the serologic response in vaccinated and unvaccinated mumps cases during an epidemic

“…Although the humoral response certainly plays a role in protection against mumps, it should be considered that in vitro measured VN antibody concentrations, but also IgG concentrations, may not be fully predictive of immunological antibody activity in vivo, given that Fc-mediated phagocytosis, antibody-dependent cell-mediated cytotoxicity, and other processes that occur in the host are not reflected in the corresponding assays. 32 Additionally, other immune mechanisms, such as cellular immunity, are likely involved in the protection against mumps disease as well as in the viral clearance. The cellular immunity against mumps has only been scarcely explored and deserves more attention.…”

Estimates of Mumps Seroprevalence May Be Influenced by Antibody Specificity and Serologic Method

“…Although neutralizing antibody is thought to be essential for protection (40) and PRN titration is generally considered to be the gold standard for mumps serology, previous attempts to determine a reliable threshold for protective PRN titers have been unsuccessful (20). To add further ambiguity, there have been several reports of poor correlations between mumps PRN titration and various other serologic methods, such as ELISA and immunofluorescent assays (IFA) (25)(26)(27)(28)(29)(30)(31)(32)(33)(34).…”

“…As a result, it was not possible to accurately predict the long-term persistence of antibodies or the long-term protective efficacy of the vaccine based on these data. A recent attempt to define a protective threshold for neutralizing antibody titer was inconclusive, partly due to the use of convenience samples that were not collected at ideal times and the inclusion of a limited number of cases (20). Nevertheless, the data indicate that case patients had lower neutralizing antibody titers (specific for the Jeryl Lynn strain) than nonpatients who had no known mumps exposure (P ϭ 0.023).…”

“…The consequences of less-thanoptimal vaccine effectiveness could be compounded by incomplete vaccination coverage, waning immunity, and a lack of asymptomatic natural boosting due to substantially reduced endemic disease. A common element in some recent outbreaks has been the presence of environmental conditions that foster frequent, high-intensity exposures, such as those found in dormitories (4,19,20). In light of these observations, it has been suggested that protection against classic mumps symptoms may not be an all-or-none phenomenon but may be a continuum that is a function of the amount of virus an individual is exposed to and their personal level of immunity (19,20).…”

“…Nevertheless, the data indicate that case patients had lower neutralizing antibody titers (specific for the Jeryl Lynn strain) than nonpatients who had no known mumps exposure (P ϭ 0.023). Relative to nonpatients, proportionately more case patients had neutralizing titers of Ͻ31, and antibody titers among case patients were also lower than those of nonpatients when measured by enzyme-linked immunosorbent assay (ELISA) (20).…”