Disclosed is the use of a multivalent meningococcal vaccine comprising a mixture of four distinct and separately made protein-capsular polysaccharide conjugates for the manufacture of a medicament for inducing a serum bactericidal antibody protective immune response against capsular polysaccharides of Neisseria meningitidis serogroups A, C, W-135 and Y in a human patient, wherein each of the conjugates comprises a purified capsular polysaccharide from a different serogroup of N. meningitidis conjugated to a carrier protein, further wherein said carrier protein is selected from the group consisting of diphtheria toxoid, CRM197 and tetanus toxoid, and wherein each capsular polysaccharide is selected from the group consisting of capsular polysaccharides from N. meningitidis serogroups A, C, W-135 and Y, further wherein each capsular polysaccharide is depolymerized to an average size of less than 100,000 daltons and each protein-polysaccharide conjugate has an average polysaccharide to protein ratio of 0.05 to 2.
