Meningococcal vaccines also vary by the number of serogroups they provide protection against. Both recombinant protein vaccines are monovalent vaccines. This means the Food and Drug Administration licensed them to provide protection against 1 serogroup (B). In contrast, the conjugate vaccines provide protection against 4 serogroups (A, C, W, and Y), making them quadrivalent vaccines. About Meningococcal Vaccines | CDC