Persistence of Protective Antibody Titers 12-24 Months After NmVac4-A/C/Y/W-135-DT Vaccination: Follow Up Study

Overview

To determine the persistence of protective antibody levels for subjects who seroconverted after vaccination with NmVac4-A/C/Y/W-135-DT™ Participants in trial # JN-NM-002, who seroconverted for serogroups A and C will be contacted and asked to provide a blood sample at 12-24 months after vaccination with NmVac4-A/C/Y/W-135-DT. Serum Bactericidal Assays will be performed to evaluated duration of protective antibody titer for NmVac4-A/C/Y/W-135-DT for all four serogroups. To determine if subjects who seroconverted with lower titers retain protective levels of antibody (titer ≥:8) at 12-24 months after vaccination.

The purpose of this study is to collect serum samples to evaluate duration of protection for NmVac4-A/C/Y/W-135-DT, based on titers determined by Serum Bactericidal Assay with human complement (hSBA). This assay is used to evaluate immunogenicity of meningococcal vaccines, as a surrogate for efficacy. A titer ≥ 1:8 is considered protective. Objectives are to evaluate duration of protective antibody titer for NmVac4-A/C/Y/W-135-DT for all four serogroups, and determine if subjects with lower titers, but ≥:8 retain protective levels of antibody at 12-24 months. Participants in trial # JN-NM-002, who seroconverted for serogroups A and C will be contacted and asked to provide a blood sample at 12-24 months after vaccination with NmVac4-A/C/Y/W-135-DT™. Serum Bactericidal Assays will be performed to evaluated persistence of protective antibody titer for NmVac4-A/C/Y/W-135-DT for all four serogroups, to determine if subjects who seroconverted with lower titers retain protective levels of antibody (titer ≥:8) at 12-24 months after vaccination.

Conditions