Meningococcal disease: the advances and challenges of meningococcal disease prevention

Vaccination as a means to prevent meningococcal disease caused by Neisseria meningitidis is critical given the abrupt onset and rapid progression of this disease. Five serogroups--A, B, C, W-135, and Y--are responsible for the majority of cases. In developed countries, infants have the greatest risk of disease, with a smaller secondary peak observed in late adolescence. Vaccines utilizing the polysaccharide capsule are poorly immunogenic in young children but can reduce the incidence of meningococcal carriage in high risk groups. In contrast, protein conjugate vaccines to polysaccharide capsules A, C, W-135, and Y have broadened the population protection from disease but their effect on meningococcal carriage and transmission is yet unknown except for monovalent meningococcal C conjugate that has been shown to reduce carriage. Challenges remain in providing direct protection to infants and protection against meningococcal B disease. To date, outer membrane vesicle vaccines have been used to control meningococcal B disease in epidemic settings and vaccine candidates against subcapsular antigens are in development, but a vaccine that confers long-lasting protection is unavailable.