The purpose of this study is to evaluate the safety and immunogenicity of mumps vaccine in healthy infants aged 8-12months, compared with measles, mumps and rubella combined vaccine, live (MMRV).

The study is a randomized, double-blind, controlled phase Ⅳ clinical trial. And 920 infants will be assigned to investigational group and controlled group in a 1:1 ratio. The investigational vaccine is manufactured by Sinovac (Dalian) Vaccine Technology Co., Ltd. The controlled vaccine is manufactured by Shanghai institute of biological products Co., Ltd.

Inclusion Criteria:

• Healthy volunteers between 8 - 12 months old;
• Proven legal identity;
• Written consent of the guardian(s) of the volunteer

Exclusion Criteria:

• Received mumps vaccine or vaccine containing mumps virus;

• History of mumps;

• Axillary temperature > 37.4 °C;

• History of allergy to any vaccine or vaccine ingredient;

• History of serious adverse reaction(s) to vaccination, such as urticaria, difficulty in breathing, angioneurotic edema, abdominal pain, etc;

• Autoimmune disease or immunodeficiency or immunosuppression;

• Congenital malformation, genetic defects, severe malnutrition;

• Diagnosed coagulation function abnormal (e.g., coagulation factor deficiency, coagulation disorder, or platelet abnormalities) , or obvious bruising or coagulation disorders;

• Severe chronic diseases (e.g., severe cardiovascular disease, liver and kidney disease beyond the control of drugs, or cancer)

• Severe neurological disorders (epilepsy, seizures or convulsions) or psychosis;

• History of thyroidectomy, absence of spleen, functional absence of spleen, and any condition resulting from absence of spleen or splenectomy;

• Receipt of any of the following products:

  1. Any subunit vaccine or inactivated vaccine within 7 days prior to study entry;
  2. Any live attenuated vaccine within 28 days prior to study entry;
  3. Any other investigational medicine(s) or vaccine within 30 days prior to study entry;
  4. Blood product within 3 months prior to study entry;
  5. Any immunosuppressant, cytotoxic medicine, or oral corticosteroids;
  6. Any of the acute disease or attack of the chronic disease within 7 days;
  7. Pregnant in cohabitants or congenital immune diseases;
  8. Based on the judgment of investigator(s), there was any condition indicating that the subject should be excluded