A Study to Demonstrate Non-inferior Immunogenicity of Yuxi Walvax MPV ACYW® Vaccine in Healthy Subjects Aged 2-10 Years

This is a phase IV, single-center, observer-blind, randomized, controlled vaccine trial in 2 to 10 years old healthy subjects. Each participant will receive a single intramuscular injection of one of the two vaccines either MPV ACYW® vaccine or Menactra ® vaccine according to the vaccine group assignment and will be followed up for one month for immunogenicity evaluation and for 6 months for safety evaluation.

Statistical Hypothesis:

H0: Seroconversion rate of test group is inferior to that of control group HA: Seroconversion rate of test group is non-inferior to that of control group Sample size calculation: the sample size was calculated based on non-inferiority test with alpha level of 0.025 and 80% power, assuming seroconversion rate in control group was 95% with non-inferiority margin at 10%. The sample size required for the study is 124 per arm. After adjusting for 5% drop-out, the final sample size required is 130 per arm.


Eligibility Criteria:
Inclusion Criteria:

* Age 2 to 10 years of age (both included)
* Written informed consent obtained from the mother, father, or guardian of the child.
* Free of obvious health problems and be fully vaccinated according local EPI schedule as established by medical history including physical examination and clinical judgment of the investigator.
* Mother, father, or guardian capable and willing to bring their child or to receive home visits for their child for all follow-up visits.
* Residence in the study area during the study period.

Exclusion Criteria:

* Vaccination against group A,C,Y,W Neisseria meningitidis in the previous 3 months
* History of allergic disease or known hypersensitivity to any component of the two study vaccines.
* History of serious adverse reactions following administration of vaccines included in the local program of immunization.
* Administration of any other vaccine within 30 days prior to administration of study vaccines or planned vaccination during the first four weeks after the study vaccination.
* Use of any investigational or nonregistered product within 60 days prior to the administration of study vaccines.
* Administration of immunoglobulins and/or any blood products or planned administration during the study participation period.
* Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying agents since birth (including systemic or inhaled corticosteroids, this means prednisone, or equivalent, ≥0.5 mg/kg/day; topical steroids are allowed).
* A family history of congenital or hereditary immunodeficiency.
* History of meningitis or seizures, or any neurological disorder, convulsions, or active tuberculosis.
* Major congenital defects or serious chronic illness, including malnutrition (i.e., weight less than or equal to 3 standard deviations below the mean for 2-5 years old) and immunodeficiency disorder (as per investigator's judgment)
* Acute disease at the time of enrollment (acute disease being defined as the presence of a moderate or severe illness with or without fever) resulting in a temporary exclusion.
* Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic, or renal functional abnormality, as determined by medical history, physical examination, or laboratory tests, which in the opinion of the investigator might interfere with the well-being of the subject study objectives.
* Any condition or criterion that in the opinion of the investigator might compromise the well-being of the subject or the compliance with study procedures or interfere with the outcome of the study