Antibody Persistence 1-5 Years Following Vaccination With MenAfriVac in African Children Vaccinated at 12-23 Months of Age.

The “meningitis belt” of sub-Saharan Africa runs across the continent from Senegal to Ethiopia, and this region is prone to major epidemics of meningococcal meningitis, with a high case fatality rate and serious sequelae. Until recently, most epidemics were due to group A Neisseria meningitidis (MenA). The observed reduction in meningococcal meningitis due to MenA has been due to the development of an affordable group A meningococcal vaccine, PsA-TT (MenAfriVac, Serum Institute of India, Ltd). The Meningitis Vaccine Project, a partnership between the World Health Organization (WHO) and PATH, coordinated the development, testing, licensure, and introduction of this vaccine with the aim of eliminating epidemic meningitis attributable to MenA [1–4]. Since 2010, PsA-TT has been introduced into countries across the meningitis belt through mass campaigns [5, 6]. PsA-TT is expected to confer both longer-lasting individual protection and herd protection than MenA polysaccharide vaccines. Ongoing surveillance shows that no cases of MenA meningococcal disease have occurred in vaccinated individuals [6], but the longevity of this protective immune response is not known. Prior to the introduction of PsA-TT into the African countries of the meningitis belt, multiple clinical trials assessed the safety and immunogenicity of PsA-TT. A trial conducted in children aged 12–23 months demonstrated that this vaccine was immunogenic and induced immune memory. However, antibody persistence is key in maintaining direct and indirect protection [7, 8]. We report here on the persistence of MenA-specific antibodies in individuals vaccinated with PsA-TT in early childhood.