Serogroup A meningococcal conjugate vaccines: building sustainable and equitable vaccine strategies

ABSTRACT

Introduction

For well over 100 years, meningococcal disease due to serogroup A Neisseria meningitidis (MenA) has caused severe epidemics globally, especially in the meningitis belt of sub-Saharan Africa.

Areas covered

The article reviews the background and identification of MenA, the global and molecular epidemiology of MenA, and the outbreaks of MenA in the African meningitis belt. The implementation (2010) of an equitable MenA polysaccharide-protein conjugate vaccine (PsA-TT, MenAfriVac) and the strategy to control MenA in sub-Saharan Africa is described. The development of a novel multi-serogroup meningococcal conjugate vaccine (NmCV-5) that includes serogroup A is highlighted. The PubMed database (1996–2019) was searched for studies relating to MenA outbreaks, vaccine, and immunization strategies; and the Neisseria PubMLST database of 1755 MenA isolates (1915–2019) was reviewed.

Expert opinion

Using strategies from the successful MenAfriVac campaign, expanded collaborative partnerships were built to develop a novel, low-cost multivalent component meningococcal vaccine that includes MenA. This vaccine promises greater sustainability and is directed toward global control of meningococcal disease in the African meningitidis belt and beyond. The new WHO global roadmap addresses the continuing problem of bacterial meningitis, including meningococcal vaccine prevention, and provides a framework for further reducing the devastation of MenA.

KEYWORDS:

• Neisseria meningitidis
• serogroup A
• conjugate vaccine
• immunization strategies

Article highlights

• Significant and devastating outbreaks of serogroup A meningococcal disease caused high morbidity and mortality globally, especially in the meningitis belt of Africa from 1905-2010.

• Through a unique partnership with both private and public sectors, a highly immunogenic serogroup A polysaccharide conjugate vaccine (PsA-TT, MenAfriVac) was created and implemented in the meningitis belt 2010-present.

• Although the MenAfriVac campaign has been highly successful and has virtually eliminated serogroup A meningitis from sub-Saharan Africa, the challenge is to identify and prevent other serogroups of N. meningitidis in the belt, as well as to maintain immunity and protection against serogroup A.

• A new low-cost multivalent (PsA-TT, PsC-CRM₁₉₇, PsY-CRM₁₉₇, PsW-CRM₁₉₇, PsX-TT; NmCV-5) meningococcal conjugate vaccine is being developed and tested in clinical trials that not only cover serogroup A but also protects against other serogroups which continue to cause outbreaks in sub-Saharan Africa.

• The WHO and partners have developed a roadmap ‘Defeating meningitis by 2030’ to further reduce the global burden of meningitis due to MenA and the acute bacterial meningitis pathogens.

Acknowledgments

The authors would like to thank Dianne Watson for her contributions to manuscript preparation and to the work of the WHO “Defeating Meningitis by 2030” Taskforce.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This work was supported by Emory University and NIH training grants (VTP-T32 T32AI074492)