A-322 ELISA-based determination of anti-mumps IgG reveals a prevalence of 80 percent in sera obtained in Brazil

Background The incidence of mumps virus (MV) infection has declined worldwide as a result of national immunization programs. However, outbreaks have still occurred in different countries due to low vaccination efficiency, acceptance, or accessibility. Detection of serum IgG antibodies against MV-specific antigens can indicate the immune status of individuals after vaccination or infection. This study investigates the presence of anti-MV IgG using two different ELISAs to determine the prevalence in sera obtained in Brazil. Methods Presence of anti-MV IgG was determined in sera from 357 individuals from São Caetano do Sul, Brazil, using the EUROIMMUN Anti-Mumps Virus ELISA containing the MV wild type antigen and the EUROIMMUN Anti-Mumps Virus AT ELISA containing antigens of both the MV wild type and the Jeryl Lynn vaccination strain. Participants reported past MV infection (n=129), vaccination (n=246, of those n=124 during early childhood, n=65 between 11–19, and n=57 between 20–59 years of age), and unknown status (n=73). Results Using the Anti-Mumps Virus and Anti-Mumps Virus AT ELISAs, an overall prevalence for anti-MV IgG of 64.7% (50.1% positive, 14.6% borderline) and 80.1% (70.0% positive, 10.1% borderline) was found, respectively. In the subpanel with reported past MV infection, 76.7% (65.1% positive, 11.6% borderline) and 89.1% (79.8% positive, 9.3% borderline) of sera were reactive. The share of reactive sera in the subpanels with reported vaccination between 11–19 years of age was 61.5% (40.4% positive, 21.1% borderline) and 75.4% (61.4% positive, 14.0% borderline) and between 20–59 years of age 69.2% (60.0% positive, 9.2% borderline) and 86.1% (76.9% positive, 9.2% borderline). Conclusion In this study, the Anti-Mumps Virus AT ELISA showed a higher anti-MV IgG positivity rate than the Anti-Mumps ELISA. The resulting higher prevalence is consistent with the reported medical history of the individuals. The high detection rate even years after antigen exposure proves the applicability of the Anti-Mumps Virus AT ELISA in seroepidemiological studies.