Simplifying Meningococcal Conjugate Vaccination

April 8, 2015

Simplifying Meningococcal Conjugate Vaccination

  1. Robert S. Baltimore, MD

One priming dose of MenC-CRM plus booster was more immunogenic than two priming doses; a single dose of MenC-TT plus booster was better still.

  1. Robert S. Baltimore, MD

The first effective meningococcal (Men) vaccines, which consisted of capsular polysaccharides from meningococci of the respective serogroups, are not immunogenic in children aged <2 years. Conjugation of the polysaccharides to a protein carrier has resulted in vaccines (Men, as well as Haemophilus influenzae type b [Hib] and Streptococcus pneumoniae) that are immunogenic even in young infants. In a partially industry-supported, phase IV, open-label, controlled trial conducted in the U.K. and Malta, researchers compared two such vaccines — MenC-CRM (which uses CRM97 protein, a nontoxic mutant of diphtheria toxoid) and MenC-TT (a MenC polysaccharide–tetanus toxoid formulation) — to determine the most-effective serogroup C Men conjugate vaccination schedule.

The 509 infant vaccinees were randomized in a 10:10:7:4 ratio to receive a single priming dose of MenC-CRM at age 3 months; two doses of MenC-CRM, at 3 and 4 months; MenC-TT at 3 months; or no Men priming dose. All participants received Hib–MenC-TT at 12 months. Blood samples were taken at 5, 12, 13, and 24 months to determine MenC bactericidal antibody titers.

At 13 months, the immunogenicity of one priming dose of MenC-CRM was superior to that of two MenC-CRM doses; the immunogenicity of MenC-TT after a single priming dose was superior to that seen in either MenC-CRM group. At 24 months, the titers had dropped in all groups; they remained protective (≥1:8) in 82% of the Men-TT group compared with only 20% and 31% in the two- and one-dose MenC-CRM groups, respectively.


Although many other countries recommend MenC vaccination in infancy, the U.S. does not. Countries where MenC vaccination is given routinely vary as to the number and timing of doses. If the U.S. recommendations change, these findings support a single infant priming dose, as is done currently in the U.K.

Editor Disclosures at Time of Publication

  • Disclosures for Robert S. Baltimore, MD at time of publication Editorial boards Current Opinion in Pediatrics; Infectious Diseases in Children Leadership positions in professional societies Member Committee on Rheumatic Fever, Endocarditis and Kawasaki Disease


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