Association of meningococcal serotypes with the course of disease: serotypes 2a and 2b in the Netherlands, 1959-1981.

Case histories of 692 patients with meningococcal disease due to serogroup B, C, or W (W-135) were reviewed to study the association of the serotypes 2a and 2b with the course of disease. The case-fatality rate in group B disease was significantly associated with serotype 2b (B:2b) strains (P = 0.03). Age and year of admission did not account for this association. Septicemia was also found more frequently with B:2b than with other B serotypes, but neurological complications and sequelae were not. Neither C:2a nor W:2a was associated with a higher case-fatality rate, with more cases of septicemia, or with more sequelae than were other C or W serotypes. We concluded that the 2b antigen, although not likely a causal factor, is a virulence marker among group B strains and that the protective effect of a vaccine containing this protein (among others) needs to be studied.