Efficacy and Effectiveness of the Meningococcal Conjugate Group A Vaccine MenAfriVac ® in Preventing Recurrent Meningitis Epidemics in Sub-Saharan Africa

• Published in: Vaccines (Basel) 2022-04, Vol.10 (4), p.617
• Main Author: Viviani, Simonetta
• Format: Article
• Language: English
• Subjects: Antibodies; Antigens; Appropriate technology; Children; Collaboration; conjugate meningococcal vaccine; Conjugates; Diphtheria; Disease; effectiveness; efficacy; Epidemics; Herd immunity; Immunization; Immunogenicity; Immunological memory; Immunology; Infants; Licenses; Meningitis; meningitis epidemic; Meningococcal disease; Morbidity; Mortality; Neisseria meningitidis serogroup A; Polysaccharides; Proteins; Public health; Review; Seat belts; sub-Saharan Africa; Tetanus; Vaccination; Vaccines
• ISSN: 2076-393X; 2076-393X
• DOI: 10.3390/vaccines10040617

For more than a century, epidemic meningococcal disease mainly caused by serogroup A has been an important public health problem in sub-Saharan Africa. To address this problem, an affordable meningococcal serogroup A conjugate vaccine, MenAfriVac , was developed specifically for populations in the African meningitis belt countries. MenAfriVac was licensed based on safety and immunogenicity data for a population aged 1-29 years. In particular, the surrogate markers of clinical efficacy were considered to be the higher immunogenicity and the ability to prime immunological memory in infants and young children compared to a polysaccharide vaccine. Because of the magnitude of serogroup A meningitis epidemics and the high morbidity and mortality burden, the World Health Organization (WHO) recommended the MenAfriVac deployment strategy, starting with mass vaccination campaigns for 1-29-year-olds to rapidly interrupt serogroup A person-to-person transmission and establish herd protection, followed by routine immunization of infants and toddlers to sustain protection and prevent epidemics. After licensure and WHO prequalification of MenAfriVac , campaigns began in December 2010 in Burkina Faso, Mali, and Niger. By the middle of 2011, it was clear that the vaccine was highly effective in preventing serogroup A carriage and disease. Post introduction meningitis surveillance revealed that serogroup A meningococcal disease had disappeared from all age groups, suggesting that robust herd immunity had been achieved.