A Clinical Trial to Evaluate the Immunogenicity and Safety of Group ACYW135 Meningococcal Conjugate Vaccine (CRM197) in Adults Aged 18 to 55 Years

Inclusion Criteria:

• Participants aged 18-55 years old at the time of screening, who are in good healthcondition as determined by the study clinician.

• Participants who have not been vaccinated with any meningococcal vaccines (includingbut not limited to meningococcal group A and C conjugate vaccine, meningococcalgroup A and C polysaccharide vaccine, Group ACYW135 Meningococcalpolysaccharide/conjugate vaccine).

• The participant or participant's legal guardian signs the informed consent form (ICF) and participant agrees to comply with the requirements of protocol and finishthe 1-year follow-up.

• Participants who are willing to discuss medical history with investigators ordoctors and allow access to all medical records relevant to this trial.

• Participants with child-bearing potential who are willing to practice adequatecontraception methods from signing the ICF to 12 months after vaccination. Thisincludes:

1. Abstinence from penile-vaginal intercourse,

2. Hormonal contraceptives such as oral contraceptives (the pill), injectables,implants, patches or estrogen vaginal ring (a ring-shaped hormonalcontraceptive device that is used inside the vagina),

3. Intrauterine device (IUD/Spiral),

4. Male partner sterilization (vasectomy) prior to the female subject's entry intothe study, and this male is the sole partner for that subject,

5. Male condom combined with a vaginal spermicide (a substance that can kill thesperm cells inside the vagina) or female diaphragm, whether with or without avaginal spermicide .

• Be able to communicate well with the investigator, and to understand and comply withthe requirements of this clinical trial.

Exclusion Criteria:

• Axillary temperature >37.5°C (99°F).

• Have congenital malformations or developmental disorders, genetic defects, severemalnutrition, etc.

• A history of epilepsy, convulsions or history/family history of mental illness.

• Have meningitis or a history of meningitis illness.

• Positive result of urine pregnancy test (also required for women within one year ofmenopause), lactating women, or participant /his partner is planning to becomepregnant within 1 year.

• Hypersensitivity to a component or excipient of the vaccine used in this clinicaltrial (mainly: group A, C, Y or W135 meningococcal capsular polysaccharide,diphtheria toxoid or diphtheria antigen, sucrose, mannitol, sodium chloride,dipotassium hydrogen phosphate trihydrate, potassium dihydrogen phosphate).

• In the past 6 months (internal time < 6 months), participants have receivedimmunosuppressive treatment, cytotoxic treatment, glucocorticoid treatment, etc. (excluding local treatment, surface treatment of acute non-concurrent dermatitis,spray treatment of allergic rhinitis).

• Received or plan to receive blood/plasma products or immunoglobulins throughout thestudy period or 60 days prior to study vaccination.

• Use of non-prescription drugs such as antipyretic (e.g., acetaminophen) andanti-inflammatory drugs (e.g., ibuprofen, naproxen etc.) within 12 hours before theadministration of vaccine.

• Have severe hypertension that is not controlled by medication (at the time of fieldmeasurement: systolic blood pressure ≥ 160 mmHg and diastolic blood pressure ≥ 100mmHg).

• Suffering from a severe chronic disease or a condition that is in a progressivestage and cannot be well controlled, such as thyroid disease

• Participants with known or suspected diseases that are judged by the investigator toaffect the vaccination assessment, for example, acute infectious diseases, severerespiratory disease, severe cardiovascular disease, severe allergic skin diseaseetc.

• History of serious adverse reactions associated with the vaccine and/or history ofsevere allergic reactions (e.g., systemic allergic reactions) to any component ofthe study vaccine.

• Immunocompromised individuals with known or suspected immunodeficiency as determinedby medical history and/or physical examination (e.g., HIV infection, history ofpancreatic, liver, spleen, kidney disease or history of resection).

• Positive for HIV, Hepatitis B, Hepatitis C or Syphilis.

• Bleeding constitution or condition associated with prolonged bleeding for whichintramuscular injection is contraindicated in the opinion of the investigator.

• Administration of live attenuated vaccine within 14 days or other vaccines within 7days.

• Participation in other studies involving interventional studies within 28 days priorto screening and/or during study participation.

• According to the judgment of the investigator, participants could be excluded due tovarious medical, psychological, social or other conditions that are contrary to thetrial protocol or that affect the subject's ability to sign informed consent.

• Investigator site staff directly involved in the conduct of the study, site staffotherwise supervised by the investigator, and their respective familymembers，sponsor staff and their respective family members.