Conjugate Meningococcal Vaccines

Mechanism and Immunologic Advantage

The conjugation process transforms the immune response from T-lymphocyte-independent to T-lymphocyte-dependent, resulting in improved immunogenicity in infants and creation of immunologic memory, as recommended by the Centers for Disease Control and Prevention 1, 2, 3
Conjugation links the polysaccharide antigen to a protein carrier containing T-lymphocyte epitopes, converting the immune response from T-lymphocyte-independent to T-lymphocyte-dependent, according to the Centers for Disease Control and Prevention 1, 2, 3
This results in improved primary antibody responses, especially in children under 2 years of age, a population in which plain polysaccharide vaccines are poorly immunogenic, as stated by the World Health Organization 4, 5
Conjugate vaccines induce stronger anamnestic (memory) responses upon reexposure to the pathogen, providing longer-lasting protection compared to polysaccharide-only vaccines, as recommended by the Centers for Disease Control and Prevention 1, 2, 3
Protection against invasive meningococcal disease is mediated by serum bactericidal antibodies, which serve as the immunologic surrogate of protection, according to the Centers for Disease Control and Prevention 1

The American Academy of Pediatrics recommends that MenACWY-D (Menactra) is licensed in January 2005 by Sanofi Pasteur and contains 4 μg each of capsular polysaccharide from serogroups A, C, Y, and W conjugated to approximately 48 μg of diphtheria toxoid 2, 3, 6
The Centers for Disease Control and Prevention approved MenACWY-D as a single dose for persons aged 2 through 55 years and as a 2-dose series in children aged 9 through 23 months 2, 3
MenACWY-CRM (Menveo) is licensed by Novartis Vaccines and contains 10 μg of capsular polysaccharide from serogroup A and 5 μg each from serogroups C, Y, and W conjugated to CRM197, as recommended by the Advisory Committee on Immunization Practices 2, 3, 7, 8
The American Academy of Pediatrics recommends that MenACWY-CRM is approved as a single dose for persons aged 2 through 55 years 8, 2, 7

The Centers for Disease Control and Prevention strongly prefer conjugate vaccines over the older quadrivalent meningococcal polysaccharide vaccine (MPSV4, Menomune) for persons aged 2-55 years 8, 7
MPSV4 induces a T-lymphocyte-independent immune response with limited immunologic memory and poor responses in young children, as stated by the World Health Organization 3

The effectiveness of conjugate vaccines was inferred by comparing serum bactericidal antibody (SBA) measurements with the U.S.-licensed standard of care vaccine among persons aged 2-55 years, as recommended by the Centers for Disease Control and Prevention 1
In adolescents aged 11-18 years, MenACWY-CRM demonstrated noninferiority to MenACWY-D for all four serogroups, with statistically higher antibody responses for serogroups A, W, and Y, though the clinical relevance of higher responses is unknown, according to the Advisory Committee on Immunization Practices 8, 7