A Phase 3, Double-Blind, Randomized, Active Controlled Study to Evaluate the Safety of MenAfriVac in Healthy Malians

Controlling group A meningococcal disease is a public health priority. Every 10–12 years, the region of sub-Saharan Africa extending from Senegal to Ethiopia, known as the meningitis belt, experiences major epidemics of meningococcal meningitis [1]. These epidemics have been most commonly caused by group A Neisseria meningitidis. Since 2001, the Meningitis Vaccine Project, a partnership between the World Health Organization (WHO) and PATH, funded by the Bill & Melinda Gates Foundation, has aimed to eliminate group A meningococcal disease through the development of an affordable group A meningococcal conjugate vaccine that induces immunologic memory and a long-lasting immune response [2]. This effort led to the licensure, followed by WHO prequalification, of PsA-TT (MenAfriVac, Serum Institute of India, Ltd) in June 2010 after 4 clinical studies (phase 1, 2, and 2/3) that included a total of 1915 subjects, of whom 1126 from age 1 to 34 years had received at least 1 dose of PsA-TT, and which demonstrated its safety and superior immune response compared with the group A–containing polysaccharide vaccine [3–8]. Two additional clinical studies (phase 3), a lot consistency study in India and a large safety study in Africa, were ongoing at the time of prequalification and submitted to regulatory authorities as part of the early postlicensure requirements. Here we present the results of the large phase 3 safety trial conducted in 2010 in Bamako, Mali, to collect additional data on the safety profile of PsA-TT in a randomized controlled setting [9–12], while allowing sufficient exposure to detect potential rare vaccine-related adverse reactions, where “rare” is conventionally defined as ≤1 per 1000 vaccinees [13].