Meningococcal quadrivalent ACYW-TT conjugated vaccine at 6-23 months: phase III study (US/Puerto Rico)

Area of Science:

• Vaccinology
• Immunology
• Pediatric Infectious Diseases

Background:

• Development of a quadrivalent meningococcal tetanus toxoid-conjugate vaccine (MenACYW-TT) for broad protection against invasive meningococcal disease.
• Evaluation of MenACYW-TT's immunogenicity and safety in a two-dose series co-administered with routine pediatric vaccines.
• Study focused on infants from 6 months of age.

Purpose of the Study:

• To evaluate the immunogenicity and safety of the MenACYW-TT vaccine in a two-dose series for infants and toddlers.
• To compare MenACYW-TT's performance against existing quadrivalent meningococcal conjugate vaccines.
• To support the use of MenACYW-TT in pediatric immunization schedules.

Main Methods:

• Phase III, modified double-blind, randomized study (NCT03691610) involving 950 healthy infants and toddlers.
• Infants (6-7 and 12-13 months) and toddlers (17-19 and 20-23 months) received either MenACYW-TT or comparator vaccines.
• Immunogenicity assessed via serum bactericidal antibody assay (hSBA); safety monitored for 6 months post-vaccination.

Main Results:

• MenACYW-TT demonstrated non-inferior seroresponse rates compared to MenACWY-CRM across all four meningococcal serogroups.
• Seroresponse rates post-second dose ranged from 89.4-99.3% for MenACYW-TT and 82.9-97.7% for MenACWY-CRM.
• All tested vaccines were well tolerated, indicating favorable safety profiles.

Conclusions:

• The two-dose MenACYW-TT series administered from 6 months of age is immunogenic and safe.
• Findings support the use of MenACYW-TT as a viable option for meningococcal disease prevention in children.
• The study provides evidence for MenACYW-TT's comparable or superior immunogenicity and similar safety profile to existing vaccines.