Evolving meningococcal immunization strategies

Abstract

Meningococcal disease is a major public health problem and immunization is considered the best strategy for prevention. The introduction of meningococcal C conjugate immunization schedules that targeted adolescents, with catch-up programs in several European countries, Australia and Canada proved to be highly effective, with dramatic reduction in the incidence of serogroup C disease, not only in vaccinated, but also in unvaccinated individuals. Meningococcal quadrivalent (A, C, W, Y) conjugate vaccines are now licensed and are being used in adolescent programs in North America and to control serogroup W disease in South America. In the African meningitis belt, a mass immunization campaign against serogroup A disease using a meningococcal A conjugate vaccine is now controlling the devastating epidemics of meningococcal disease. After introducing new immunization programs, it is of importance to maintain enhanced surveillance for a better understanding of the changing nature of disease epidemiology. This information is crucial for identifying optimal immunization policies.

Keywords:

• conjugate vaccine
• immunization schedule
• meningococcal
• Neisseria meningitidis
• serogroup A
• serogroup C
• serogroup W

Financial & competing interests disclosure

MA Sáfadi has received grants from Novartis, Sanofi and GSK. R Borrow performs contract research on behalf of Public Health England for Sanofi Pasteur, Sanofi Pasteur rSD, Novartis Vaccines, GSK, Baxter Biosciences, Merck and Pfizer. JA Bettinger is supported by a Michael Smith Foundation for Health Research Career Investigator Award. The authors have no other 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 apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Meningococcal conjugate vaccines, whether monovalent serogroup A or C or quadrivalent for serogroups A, C, Y and W have proved safe and effective.

• Meningococci cause serious disease worldwide with immunization being the best means of prevention.

• Meningococcal serogroup A and C monovalent conjugate vaccines were licensed and introduced on the basis of immunogenicity and safety data without Phase III effectiveness studies, thus knowledge learnt about these vaccines stems from national surveillance programs.

• For serogroup C in Europe, Canada and Australia, immunizing teenagers, the most prevalent carriers of meningococci, was important in generating herd protection.

• The monovalent serogroup A conjugate vaccine, first introduced in Africa in 2010, has already proven to prevent both serogroup A disease and the acquisition of carriage.

• Meningococcal conjugate vaccines have clearly demonstrated that their main attribute is in prevention of the acquisition of carriage and interrupting transmission, thus inducing herd protection.

• The potential for herd protection should be taken into consideration by policy makers deciding vaccine strategies.

• A serogroup B vaccine is now licensed on the basis of safety and immunogenicity data, knowledge about this vaccine will only be learnt through introduction into immunization programs and surveillance.

Notes