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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Duration of Protection Based on Persistent Antibody Titers 12-24 Months After Vaccination: Follow Up to Phase 2 Study of Meningococcal Serogroups A, C, Y & W-135 Polysaccharide Diphtheria Toxoid Conjugate Vaccine (NmVac4-A/C/Y/W-135-DT)

Conditions
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Meningococcal Meningitis, Meningococcal Infections

Intervention / Treatment
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* Biological: NmVac4-A/C/Y/W-135-DT™


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Willing and able to give informed consent Participant in trial JN-NM-002 Seroconverted in trial JN-NM-002 for both serogroups A and C Exclusion Criteria: Chronic medication use or medical history that, in the opinion of the Investigator, may impact the quality of the sample or safety of the subject

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Biological: NmVac4-A/C/Y/W-135-DT™|no intervention in this study, received test vaccine in trial JN-NM-002|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Antibody titer |  | 12-24 months after vaccination in study JN-NM-002 |