Immunogenicity, reactogenicity and persistence of meningococcal A, C, W-135 and Y-tetanus toxoid candidate conjugate (MenACWY-TT) vaccine formulations in adolescents aged 15-25 years.

Development of meningococcal serogroups A, C, W-135 and Y conjugate vaccines could expand coverage against devastating meningococcal diseases. The immunogenicity of one dose of each one of five MenACWY-TT formulations versus a licensed ACWY polysaccharide vaccine was evaluated in 175 healthy subjects of 15-25 years. Serum bactericidal titers (rSBA) were evaluated before and after vaccination. The percentage of rSBA responders to each serogroup A, C, W-135 and Y did not statistically differ from the control for each of the five formulations except for serogroup A that was lower after administration of one formulation. In the 3-year follow-up of the first study where the latter formulation was assessed, bactericidal antibody persistence was similar to the licensed ACWY polysaccharide vaccine for MenA and MenC and higher for MenW-135 and MenY. Our results present five investigational MenACWY-TT conjugate vaccine formulations which are well tolerated and highly immunogenic in adolescents.