PorA variable antigenic regions VR1, VR2, and VR3 of Neisseria meningitidis serogroups B and C isolated in Brazil from 1999 to 2004.

The high genetic diversity found among the PorA regions VR1 and VR2 of 101 Neisseria meningitidis isolates from patients with meningococcal disease and healthy carriers in Brazil contrasts with the stability found in the PorA VR3 of these isolates. The presence of VR3 epitope variant 35 or 36 on the surfaces of 87% of the strains analyzed suggests that these antigens should be considered for inclusion in new formulations of vaccines against serogroup B meningococci in Brazil.