Vaccines for prevention of group B meningococcal disease: Not your father's vaccines

For decades, there was no licensed vaccine for prevention of endemic capsular group B meningococcal disease, despite the availability of vaccines for prevention of the other most common meningococcal capsular groups. Recently, however, two new vaccines have been licensed for prevention of group B disease. Although immunogenic and considered to have an acceptable safety profile, there are many scientific unknowns about these vaccines, including effectiveness against antigenically diverse endemic meningococcal strains; duration of protection; whether they provide any herd protection; and whether there will be meningococcal antigenic changes that will diminish effectiveness over time. In addition, these vaccines present societal dilemmas that could influence how they are used in the U.S., including high vaccine cost in the face of a historically low incidence of meningococcal disease. These issues are discussed in this review.

Bactericidal antibody against a representative epidemiological meningococcal serogroup B panel confirms that MATS underestimates 4CMenB vaccine strain coverage

BACKGROUND

4CMenB (Bexsero), a vaccine developed against invasive meningococcal disease caused by capsular group B strains (MenB), was recently licensed for use by the European Medicines Agency. Assessment of 4CMenB strain coverage in specific epidemiologic settings is of primary importance to predict vaccination impact on the burden of disease. The Meningococcal Antigen Typing System (MATS) was developed to predict 4CMenB strain coverage, using serum bactericidal antibody assay with human complement (hSBA) data from a diverse panel of strains not representative of any specific epidemiology.

OBJECTIVE

To experimentally validate the accuracy of MATS-based predictions against strains representative of a specific epidemiologic setting.

METHODS AND RESULTS

We used a stratified sampling method to identify a representative sample from all MenB disease isolates collected from England and Wales in 2007-2008, tested the strains in the hSBA assay with pooled sera from infant and adolescent vaccinees, and compared these results with MATS. MATS predictions and hSBA results were significantly associated (P=0.022). MATS predicted coverage of 70% (95% CI, 55-85%) was largely confirmed by 88% killing in the hSBA (95% CI, 72-95%). MATS had 78% accuracy and 96% positive predictive value against hSBA.

CONCLUSION

MATS is a conservative predictor of strain coverage by the 4CMenB vaccine in infants and adolescents.