Diversity of Canadian meningococcal serogroup B isolates and estimated coverage by an investigational meningococcal serogroup B vaccine (4CMenB).

BACKGROUND

In collaboration with the Canadian Immunization Monitoring Program Active (IMPACT), the National Microbiology Laboratory, the UK Health Protection Agency and Novartis Vaccines, we tested the potential of an investigational 4-component meningococcal B vaccine (4CMenB) to cover Canadian strains circulating from 2006 to 2009.

METHODS

IMPACT meningococcal surveillance is population based and includes over 50% of Canadian adults and children. All isolates were characterized by Meningococcal Antigen Typing System (MATS) and sequencing for factor H-binding protein (fHbp), Neisseria Heparin Binding Antigen (NHBA) and Neisserial adhesin A (NadA).

RESULTS

In total, 157 isolates were tested. Overall, 4CMenB MATS predicted strain coverage was 66% (95% CI: 46-78%), with 26%, 29% and 11% of strains covered by one, two and three vaccine antigens, respectively. The coverage of each antigen was as follows: 13% PorA, 1% NadA, 52% fHbp and 51% NHBA. The majority of strains for clonal complex (cc) 41/44 and cc60 were covered by NHBA; the majority of strains for cc269 and cc32 were covered by fHbp and NHBA. Coverage for two prevalent strains (sequence type (ST)-269 and ST-154) was 95% and 100%, respectively.

CONCLUSIONS

4CMenB has the potential to protect against a significant proportion of Canadian invasive MenB strains.