Immunogenicity and Safety of a Booster Dose of a Quadrivalent Meningococcal Conjugate Vaccine in Children
Immunogenicity and Safety of a Booster Dose of a Quadrivalent Meningococcal Conjugate Vaccine in Children
This was an open-label, multi-center study to describe the immune persistence of the priming
 dose and describe the immunogenicity and safety of a booster dose of Meningococcal
 Polysaccharide (Serogroups A, C, Y, and W) Tetanus Toxoid (MenACYW) conjugate vaccine in
 children in Finland who had been vaccinated 3 years earlier as toddlers with either MenACYW
 conjugate vaccine or Nimenrix® as part of the MET54 study (NCT03205358).

 The objectives were:

 -  To describe the antibody persistence of meningococcal serogroups A, C, Y, and W before a
 booster dose in children who received either MenACYW conjugate vaccine or Nimenrix® 3
 years earlier as toddlers.

 -  To describe the antibody responses to meningococcal serogroups A, C, Y, and W 30 days
 after a booster dose of MenACYW conjugate vaccine in children who received either
 MenACYW conjugate vaccine or Nimenrix® 3 years earlier as toddlers.

 -  To describe the antibody responses against tetanus toxoid 30 days after a booster dose
 of MenACYW conjugate vaccine in children who received either MenACYW conjugate vaccine
 or Nimenrix® 3 years earlier as toddlers.

 -  To describe the safety profile of a booster dose of MenACYW conjugate vaccine in
 children who received either MenACYW conjugate vaccine or Nimenrix® 3 years earlier as
 toddlers.
Healthy children who were vaccinated 3 years earlier at 12 to 23 months of age in study MET54
 (NCT03205358) were eligible for enrollment. All participants received a single booster dose
 of MenACYW conjugate vaccine on Day 0. Immunogenicity was assessed at pre-vaccination and 30
 days after vaccination. Safety was assessed throughout the study period, and included
 solicited injection site and systemic reactions (Day 0 to Day 7 post-vaccination);
 unsolicited adverse events up to Day 30 (Visit 2), and serious adverse events occurring
 throughout the trial.
Inclusion Criteria:

 -  Participated in and completed (attended Visit 2) study MET54.

 -  Informed consent form had been signed and dated by the parent(s) or another legally
 acceptable representative (and by an independent witness, if required by local
 regulations).

 -  Participant and parent/legally acceptable representative were able to attend all
 scheduled visits and complied with all trial procedures.

 -  Covered by health insurance where applicable.

 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 might be received at a gap of at least 2 weeks before or after the study
 vaccines. This exception includes monovalent pandemic influenza vaccines and
 multivalent influenza vaccines. If the participant was due to receive vaccination(s)
 recommended for his/her age by the national immunization schedule at the time of the
 study, the participant was recommended to complete his/her immunization schedule after
 Visit 2.

 -  Previous vaccination against meningococcal disease with either the trial vaccine or
 another vaccine (i.e., mono- or polyvalent, polysaccharide, or conjugate meningococcal
 vaccine containing serogroups A, C, Y, or W; or meningococcal B vaccine) with the
 exception of the single dose of meningococcal vaccine administered as part of study
 MET54.

 -  Receipt of immune globulins, blood or blood-derived products in the past 3 months.

 -  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 traveling 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 vaccine used in the trial or to a vaccine containing
 any of the same substances.

 -  Verbal report of thrombocytopenia, contraindicating intramuscular vaccination in the
 Investigator's opinion.

 -  Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion,
 contraindicating intramuscular vaccination.

 -  Personal history of Guillain-Barré syndrome.

 -  Personal history of an Arthus-like reaction after vaccination with a tetanus
 toxoid-containing vaccine.

 -  Chronic illness that, in the opinion of the Investigator, was 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 degree Celsius [°C]). A
 prospective participant was not included in the study until the condition had resolved
 or the febrile event had 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.