Please assess the completion status of the following clinical trial:

Trial Title: Safety and Immunogenicity Study of Inactivated Vaccine for Prevention of COVID-19

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: PARALLEL
- Observational Model: None
- Primary Purpose: PREVENTION
- Time Perspective: None
- Masking: DOUBLE
- Phase: PHASE1/PHASE2
- Number of Arms: 3.0

Eligibility Criteria:
Inclusion Criteria:~* Healthy children and adolescents aged 3-17 years;~* The subject and/or guardian can understand and voluntarily sign the informed consent form (double sign required for 8-17 years old);~* Proven legal identity.~Exclusion Criteria:~* Travel history / residence history of communities with case reports within 14 days;~* History of contact with a SARS-CoV-2 infection (positive in nucleic acid test) within 14 days;~* Have contacted patients with fever or respiratory symptoms from communities with case reports within 14 days;~* Two or more cases of fever and / or respiratory symptoms in a small contact area of volunteers, such as home, office etc. within 14 days;~* History of SARS-CoV-2 infection;~* History of asthma, history of allergy to the vaccine or vaccine components, or serious adverse reactions to the vaccine, such as urticaria, dyspnea, and angioedema;~* Congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc.;~* Autoimmune disease or immunodeficiency / immunosuppression;~* Severe chronic diseases, severe cardiovascular diseases, hypertension and diabetes that cannot be controlled by drugs, liver or kidney diseases, malignant tumors, etc.;~* Severe neurological disease (epilepsy, convulsions or convulsions) or mental illness;~* Thyroid disease or history of thyroidectomy, spleenlessness, functional spleenlessness, spleenlessness or splenectomy resulting from any condition;~* Diagnosed abnormal blood coagulation function (eg, lack of blood coagulation factors, blood coagulopathy, abnormal platelets) or obvious bruising or blood coagulation;~* Immunosuppressive therapy, cytotoxic therapy, inhaled corticosteroids (excluding allergic rhinitis corticosteroid spray therapy, acute noncomplicated dermatitis superficial corticosteroid therapy) in the past 6 months;~* Physical examination has clinically significant abnormal hematology and biochemistry laboratory test results that exceed the reference value range (only applicable to phase I clinical trials):~  1. Blood routine test: white blood cell count, hemoglobin, platelet count;~ 2. Detection of blood biochemical indicators: alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), creatinine (CR), fasting blood glucose;~ 3. Urine routine index: urine protein (PRO);~* History of alcohol or drug abuse;~* Receipt of blood products within in the past 3 months;~* Receipt of other investigational drugs in the past 30 days;~* Receipt of attenuated live vaccines in the past 14 days;~* Receipt of inactivated or subunit vaccines in the past 7 days;~* Acute diseases or acute exacerbation of chronic diseases in the past 7 days;~* Axillary temperature \>37.0°C;~* Already pregnant (including a positive urine pregnancy test) or are breastfeeding, planning to get pregnant within 3 months;~* According to the investigator's judgment, the subject has any other factors that are not suitable for participating in the clinical trial.

- Gender: ALL
- Minimum Age: 3 Years
- Maximum Age: 17 Years
- Healthy Volunteers: t

Study Arms:
- Experimental Vaccine-low dosage (Type: EXPERIMENTAL): low dosage inactivated SARS-CoV-2 vaccine
- Experimental Vaccine-medium dosage (Type: EXPERIMENTAL): medium dosage inactivated SARS-CoV-2 vaccine
- Placebo (Type: PLACEBO_COMPARATOR): No active ingredient in the placebo

Based on this trial design, predict the completion outcome and termination type (if applicable).