Immunogenicity and Safety of an Investigational Quadrivalent Meningococcal Conjugate Vaccine in Toddlers

Healthy toddlers were randomized depending on their meningococcal priming vaccination background (either meningococcal vaccine naïve or primed with MenC) and received a single dose of either MenACYW Conjugate vaccine or Nimenrix®. They were assessed for immunogenicity at baseline (pre-vaccination) and 30 to 44 days post-vaccination. Safety information were collected post-vaccination and throughout the entire study.

Inclusion criteria

• Aged 12 to 23 months on the day of the first study visit.
• Participants had received all recommended standard-of-care non-meningococcal vaccinations according to his/her age as per local regulations.
• Informed consent form (ICF) had been signed and dated by the parent/legally acceptable representative.
• Participant and parent/legally acceptable representative were able to attend all scheduled visits and complied with all trial procedures.
• Covered by health insurance if required by local regulations.
• Participants had received any meningococcal vaccine in the second year of life (i.e., from 12 months of age).
• For Inclusion in Groups 1 and 2: Participants must not had received any vaccination against meningococcal disease with either a trial vaccine or a licensed meningococcal vaccine (i.e., polyvalent, polysaccharide, or Conjugate meningococcal vaccine containing serogroups A, C, W, Y, B; or any monovalent or bivalent meningococcal vaccine).
• For Inclusion in Groups 3 and 4: Participants must had previously received at least 1 dose of licensed monovalent meningococcal C Conjugate (MenC) vaccine during infancy (i.e., before 12 months of age).

Exclusion criteria

• Participation in the 4 weeks preceding the trial vaccination or planned participation during the present trial period in another clinical trial investigating a vaccine, drug, medical device, or medical procedure.
• Receipt of any vaccine in the 4 weeks (28 days) preceding the trial vaccination or planned receipt of any vaccine prior to Visit 2 except for influenza vaccination, which may be received at least 2 weeks before or after study investigational vaccines. This exception included monovalent pandemic influenza vaccines and multivalent influenza vaccines.
• Receipt of immune globulins, blood or blood-derived products in the past 3 months.
• For Groups 1 and 2 only: Vaccination against meningococcal disease with either a trial vaccine or a licensed meningococcal vaccine (i.e., polyvalent, polysaccharide, or Conjugate meningococcal vaccine containing serogroups A, C, W, Y, B; or any monovalent or bivalent meningococcal vaccine).
• For Groups 3 and 4 only: Vaccination against meningococcal disease with either a trial vaccine or a licensed meningococcal vaccine (i.e., polyvalent, polysaccharide, or Conjugate meningococcal vaccine containing serogroups A, C, W, Y, B; or any monovalent B meningococcal vaccine), except licensed monovalent meningococcal C Conjugate (MenC) vaccination received during infancy.
• Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months).
• History of meningococcal infection, confirmed either clinically, serologically, or microbiologically.
• At high risk for meningococcal infection during the trial (specifically, but not limited to, participants with persistent complement deficiency, with anatomic or functional asplenia, or participants travelling to countries with high endemic or epidemic disease).
• Known systemic hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccines used in the trial or to a vaccine containing any of the same substances.
• Personal history of an Arthus-like reaction after vaccination with a tetanus toxoid-containing vaccine.
• Personal history of Guillain-Barré Syndrome.
• Verbal report of thrombocytopenia, as reported by the parent/legally acceptable representative contraindicating intramuscular vaccination in the Investigator's opinion.
• Bleeding disorder or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating intramuscular vaccination in the Investigator's opinion.
• Chronic illness that, in the opinion of the Investigator, is at a stage where it might interfere with trial conduct or completion.
• Moderate or severe acute illness/infection (according to Investigator judgment) on the day of vaccination or febrile illness (temperature ≥ 38.0°C). A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
• Receipt of oral or injectable antibiotic therapy within 72 hours prior to the first blood draw - Identified as a natural or adopted child of the Investigator or employee with direct involvement in the proposed study.