Phase IV Clinical Study of Immunogenicity of ACYW135 Group Meningococcal Polysaccharide Conjugate Vaccine (CRM197 Vector)

Part Ⅰ Inclusion Criteria: * Children aged 6 to 23 months at the time of screening * Volunteers who have not received any vaccine containing a epidemic encephalitis component or who have received only the group A polysaccharide flu vaccine and have been vaccinated more than 6 months since their last vaccination. 6 months or more between the last vaccination and the last vaccination * The legal guardian or delegate has given informed consent, voluntarily signed the informed consent form, and is able to comply with the requirements of the clinical study protocol Exclusion Criteria: * Fever before inoculation, axillary temperature \>37.0℃ * History of epilepsy, convulsions or seizures or history of psychiatric disorders or family history * During an acute illness episode; with a serious chronic illness or a condition that is in a progressive stage that cannot be smoothly controlled (or an acute episode) * Known allergy to a component of the vaccine, especially to diphtheria toxoid * Live attenuated vaccine received within 14 days or other vaccine received within 7 days prior to enrollment * Other circumstances that, in the judgment of the investigator, make participation in this clinical study inappropriate * Those who had a severe allergic reaction after the previous dose of vaccine * Those with serious adverse reactions causally related to the previous dose of vaccination * Newly identified or newly occurred cases after the first vaccination that do not meet the inclusion …