Antibody Persistence at 1 and 4 Years Following a Single Dose of MenAfriVac or Quadrivalent Polysaccharide Vaccine in Healthy Subjects Aged 2-29 Years.

Aldiouma Diallo,Elisa Marchetti,Richard A Adegbola,Varsha Parulekar,Fadima Cheick Haidara,Simonetta Viviani,Samba O Sow,Siddhivinayak Hirve,Olubukola T Idoko,Yuxiao Tang,Bou Diarra,Sanjay Juvekar,Prasad S Kulkarni,Helen Findlow,Ray Borrow,Ashish Bavdekar,Julie Chaumont,Lionel Martellet,Brian D Plikaytis,Marc Laforce ,George M Carlone ,Godwin Enwere ,Milagritos D Tapia ,Marie-Pierre Préziosi ,Fatoumata Diallo ,Cheryl M Elie ,Adebayo Akinsola

doi:10.1093/cid/civ518

Abstract

Background. Mass vaccination campaigns of the population aged 1–29 years with 1 dose of group A meningococcal (MenA) conjugate vaccine (PsA-TT, MenAfriVac) in African meningitis belt countries has resulted in the near-disappearance of MenA. The vaccine was tested in clinical trials in Africa and in India and found to be safe and highly immunogenic compared with the group A component of the licensed quadrivalent polysaccharide vaccine (PsACWY). Antibody persistence in Africa and in India was investigated.Methods. A total of 900 subjects aged 2–29 years were followed up for 4 years in Senegal, Mali, and The Gambia (study A). A total of 340 subjects aged 2–10 years were followed up for 1 year in India (study B). In study A, subjects were randomized in a 2:1 ratio, and in study B a 1:1 ratio to receive either PsA-TT or PsACWY. Immunogenicity was evaluated by measuring MenA serum bactericidal antibody (SBA) with rabbit complement and by a group A–specific immunoglobulin G (IgG) enzyme-linked immunosorbent assay.Results. In both studies, substantial SBA decay was observed at 6 months postvaccination in both vaccine groups, although more marked in the PsACWY group. At 1 year and 4 years (only for study A) postvaccination, SBA titers were relatively sustained in the PsA-TT group, whereas a slight increasing trend, more pronounced among the youngest, was observed in the participants aged <18 years in the PsACWY groups. The SBA titers were significantly higher in the PsA-TT group than in the PsACWY group at any time point, and the majority of subjects in the PsA-TT group had SBA titers ≥128 and group A–specific IgG concentrations ≥2 µg/mL at any point in time in both the African and Indian study populations.Conclusions. Four years after vaccination with a single dose of PsA-TT vaccine in Africa, most subjects are considered protected from MenA disease.Clinical Trials Registration. PsA-TT-003 (ISRCTN87739946); PsA-TT-003a (ISRCTN46335400).

Highlights

Mass vaccination campaigns of the population aged 1–29 years with 1 dose of group A meningococcal (MenA) conjugate vaccine (PsA-TT, MenAfriVac) in African meningitis belt countries has resulted in the near-disappearance of MenA
At 1 year and 4 years postvaccination, serum bactericidal antibody (SBA) titers were relatively sustained in the PsA-TT group, whereas a slight increasing trend, more pronounced among the youngest, was observed in the participants aged
The SBA titers were significantly higher in the PsA-TT group than in the PsACWY group at any time point, and the majority of subjects in the PsA-TT group had SBA titers ≥128 and group A–specific immunoglobulin G (IgG) concentrations ≥2 μg/mL at any point in time in both the African and Indian study populations

Summary

Methods

A total of 900 subjects aged 2–29 years were followed up for 4 years in Senegal, Mali, and The Gambia (study A). Study A Subjects were recruited at the Centre pour le Développement des Vaccins, Bamako, Mali; at the Medical Research Council Laboratories, Basse, The Gambia; and at the Institut de Recherche pour le Développement, Niakhar, Senegal. Subjects aged 2–29 years were recruited, stratified into 3 age groups of 2–10, 11–17, and 18–29 years, and randomized in a 2:1 ratio to receive either 1 dose of PsA-TT or a licensed PsACWY vaccine (Mencevax ACWY, GSK). Blood draws for immunogenicity evaluation were performed at baseline, 1 month (results described elsewhere) [7], 6 months, and 1 year after vaccination.

Results

Discussion

Conclusion