A combined approach to assess the potential coverage of a multicomponent protein-based vaccine.

Meningococcal disease caused by Neisseria meningitidis serogroup B is a public health concern even in developed countries. Despite glycoconjugate vaccines against the other invasive serogroups (A, C, W135, Y) are already available and successfully introduced in many countries, no vaccine is currently in use for prevention of serogroup B meningitis. A protein based, multicomponent vaccine (4CMenB) has been developed and proposed for prevention of invasive serogroup B meningococcal disease (MenB). This novel vaccine has been tested in clinical trials and shown to be well tolerated and immunogenic, inducing bactericidal antibodies in infants, adolescents and adults. The high level of genetic and antigenic variability observed in MenB clinical isolates, requires a suitable method to assess the ability of the 4CMenB vaccine to cover genetically diverse menigococcal strains and to estimate the potential public health impact. To this purpose the Meningococcal Antigen Typing System (MATS) has been developed and recently described. This method provides a quick and reproducible tool to estimate the level of expression and immunoreactivity of each of the vaccine antigens, in any meningococcal isolate, and it is related to the likelihood that the isolate will be killed by sera from immunized subjects. A multi-laboratory study involving several European countries, demonstrates that the 4CMenB has the potential to protect against a significant proportion of menB strains circulating in Europe.