Invasive meningococcal infections can be life-threatening and cause severe 
sequelae. Antibiotic therapy is only partially effective. Bexsero is the first 
meningococcal B vaccine to be approved in the European Union. It contains four 
capsular antigens from various strains of group B meningococci. Clinical trials 
of this meningococcal B vaccine did not assess clinical protection. Two 
immunogenicity studies in adults, one in adolescents and six in infants, are 
available. They established the immunogenicity of the meningococcal B vaccine, 
determined age-appropriate vaccination schedules, and verified that concomitant 
administration of other vaccines did not undermine its immunogenicity. In the 
absence of relevant clinical trials, an in vitro study showed that sera from 
vaccinated individuals were likely to have bactericidal activity against 85% of 
200 invasive meningococcal B strains isolated in France in 2007-2008. The 
meningococcal B vaccine provoked local adverse effects in most vaccinees, 
including local erythema, induration and pain. Fever occurred in about half of 
vaccinated children. Six cases of Kawasaki syndrome have been reported in 
children who received the vaccine, compared to only one case in control groups. 
In practice, the harm-benefit balance of this meningococcal B vaccine justify 
using it during outbreaks, provided the outbreak strain is covered by the 
vaccine antigens. Vaccinees should be enrolled in studies designed to evaluate 
clinical efficacy and to better determine the risk of Kawasaki syndrome.