A survey of serum bactericidal antibodies against neisseria meningitidis serogroups A, C, W and Y in adolescents and adults in the Republic of Korea

Background: This descriptive epidemiological study aimed to assess the prevalence of serum bactericidal antibodies against Neisseria meningitidis serogroups A, C, W and Y in adolescents and adults in the Republic of Korea. Materials and Methods: In total, 987 subjects aged 11-55 years from five geographical regions of Korea were included in the study. Human serum bactericidal assay (hSBA) was used to measure hSBA titres for serogroups A, C, W and Y. Percentages of subjects with hSBA titres ≥4 and ≥8, geometric mean titres (GMTs), and associated 95% confidence intervals (CIs), were estimated. Analysis was performed for the entire study population and stratified by age group or region. No statistical hypotheses were tested. Results: The highest percentage of subjects with hSBA titres ≥8 was observed for serogroup W (74%), was similar for serogroups C (34%) and Y (36%), and was lowest for serogroup A (9%). The percentages of subjects with hSBA titres ≥4 were similar to those with hSBA titres ≥8 for all serogroups. GMTs were 2.56 μg/mL (serogroup A), 5.14 μg/mL (serogroup C), 22.63 μg/mL (serogroup W) and 5.28 μg/mL (serogroup Y). Similar trends in GMTs across serogroups were seen for individual regions and age groups. The highest GMTs for serogroups A, W and Y were recorded in the >19-29 years group, and for serogroup C in the >49-55 years group. Across all regions, GMTs were very similar for serogroups A, C and Y, while more variation was seen for serogroup W. Conclusion: In the Korean population, among Neisseria meningitidis serogroups A, C, W and Y, serum bactericidal antibodies were most prevalent against serogroup W and least prevalent against serogroup A. These trends were maintained across age groups and regions. The highest GMTs for serogroups A, W and Y were observed in the >19-29 years group. The reasons behind the observed differences in prevalence of bactericidal antibodies against the serogroups are currently not understood, although carriage and cross-reactivity of the assay may be important influences.