Formulation and evaluation of the immunogenicity of a hexavalent Neisseria meningitidis vaccine targeted for low- and middle-income countries (LMICs) and travellers

Summary 

Neisseria meningitidis is a gram-negative diplococcus bacterium. Twelve serogroups have been identified, of which only six (A, B, C, W, X, and Y) are associated with invasive meningococcal disease (IMD). 

N. meningitidis outbreaks occur, particularly in the meningitis belt of Sub-Saharan Africa, extending from Senegal in the west to Ethiopia in the east. Notable outbreaks include serogroup X in Ghana (2000), serogroup C in Niger (2015), serogroup C in Burkina Faso (2019), and currently serogroup C in Nigeria. Outbreaks of serogroup B disease have occurred in the 1980s in Cuba, Brazil, Norway, and in the 2000s in New Zealand. Meningococcal outbreaks of serogroup W during the Hajj pilgrimage have also been documented in 2000 and 2001. The World Health Organization (WHO) has classified meningitis caused by N. meningitidis under the category of epidemic and pandemic-prone diseases. Currently, there are two pentavalent vaccines, viz., ABCWY and ACWYX, licensed. Given the potential for future outbreaks involving any of the six prevalent serogroups (A, B, C, W, X, and Y), there is an urgent need for a hexavalent vaccine. 

We are currently focusing on developing a hexavalent vaccine formulation designed to provide broad protection against N. meningitidis that combines polysaccharide conjugates from serogroups A, C, Y, W, and X with recombinant protein components, specifically factor H binding protein (fHbp) from serogroup B. Further, proof-of-concept (POC) studies will be conducted to assess its immunogenicity using the serum bactericidal antibody (SBA) assay. Our target populations include individuals in LMICs and travellers at risk.