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 encephalitiscomponent or who have received only the group A polysaccharide flu vaccine and havebeen vaccinated more than 6 months since their last vaccination. 6 months or morebetween the last vaccination and the last vaccination

• The legal guardian or delegate has given informed consent, voluntarily signed theinformed consent form, and is able to comply with the requirements of the clinicalstudy protocol

Exclusion Criteria:

• Fever before inoculation, axillary temperature >37.0℃

• History of epilepsy, convulsions or seizures or history of psychiatric disorders orfamily history

• During an acute illness episode; with a serious chronic illness or a condition thatis 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 7days prior to enrollment

• Other circumstances that, in the judgment of the investigator, make participation inthis 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 ofvaccination

• Newly identified or newly occurred cases after the first vaccination that do notmeet the inclusion criteria for the first dose or meet the exclusion criteria forthe first dose will be determined by the investigator whether to continue toparticipate in the study

Part Ⅱ

Inclusion Criteria:

• The first phase of the study has been completed, involving the (0, 3) monthvaccination schedule group for subjects aged 6 to 11 months. All subjects receivedtwo doses as required, and blood samples were collected 30 days after the primaryvaccination series.

• Children aged 3 years at the time of screening

• The trial participant is able and willing to comply with the requirements of theclinical trial protocol and can complete the 1-month study follow-up.

• The trial participants did not receive any meningococcal vaccine booster doses atage 3 years

• The legal guardian or authorized representative voluntarily signs the informedconsent form with full knowledge and understanding, and is able to comply with therequirements of the clinical research protocol.

Exclusion Criteria:

• Fever prior to vaccination, with axillary temperature >37.0°C

• History of epilepsy, convulsions, or seizures; psychiatric history or family historyof psychiatric disorders

• During acute phase of illness; severe chronic disease or progressive condition notwell controlled (or in acute phase)

• Known allergy to any vaccine component, particularly diphtheria toxoid

• Receipt of live attenuated vaccines within 14 days or other vaccines within 7 daysprior to enrollment

• Other conditions deemed ineligible for this clinical study by the investigator