The goal of this bridging study is to assess the safety and immunogenicity of BARYCELA inj. in healthy Vietnamese children aged between 12 months to 12 years. The main questions it aims to answer are:

• Safety of BARYCELA inj. (Live attenuated varicella vaccine for injection)
• Immunogenicity of BARYCELA inj. (Live attenuated varicella vaccine for injection)

Participants will be administered subcutaneously with a single dose(0.5 mL dose) of the BARYCELA inj.(MG1111) on the upper arm (brachia lateral).

Inclusion Criteria:

1. Healthy children aged 12 months to 12 years (inclusive)
2. Subject parent/legal representative willing to provide written informed consent and able to comply with the requirements for the study - Subject able to attend all scheduled visits and to comply with all study procedures
3. Negative history of Varicella and varicella vaccine
4. Subject in good health, based on medical history and physical examination
5. Having a readily identifiable place of residence in the study area, being available for the duration of trial participation, with means of telephone contact.

Exclusion Criteria:

1. Subjects who have a history of Varicella or administration of varicella vaccine
2. Subjects who have hypersensitivity reactions to the component of this Investigational Product, such as gelatin
3. Subjects with untreated active tuberculosis
4. Subjects with a history of Guillain-Barre syndrome
5. Subjects who had received salicylates (aspirin, bismuth subsalicylates) within 4 weeks before administration of investigational product or those who are planning to receive salicylates within 42 days after administration of investigational drug.
6. Subjects who administered anti-viral drug within 4 weeks before administration of investigational product or those who are planning to receive anti-viral drug within 42 days after administration of investigational drug.
7. Subjects who have had an acute febrile episode (at least 38.00C) at some time during the 72 hours before administration of investigational product or those who had any symptom suspected to be allergy including systemic rash.
8. Currently receiving or received any investigational intervention within 30 days prior to the vaccination of study vaccine.
9. Subjects who have completed vaccinations within 4 weeks before enrolment or who are planning to administer other vaccines within 42 days after administration of investigational product.
10. Administered any blood product or intravenous immunoglobulin administration within 44 weeks prior to the vaccination of study intervention
11. Currently receiving or anticipate to receive concomitant immunosuppressive or immune-modifying therapy (excluding inhaled, topical skin and/or eye drop-containing corticosteroids, low-dose methotrexate, or < 2 weeks of daily receipt of prednisone less than 20 mg for subjects who weight more than 10kg and less than 2mg/kg/day for subjects who weight less than 10kg, or equivalent) within 12 weeks prior to the vaccination of study vaccine.
12. Immunosuppressive illness or immunodeficient state, including hematologic malignancy, history of solid organ, bone marrow transplantation, or asplenia.
13. Subject with a history of hypersensitivity to any vaccine or a history of allergic disease or reactions likely to be exacerbated by any component of the study vaccine.
14. Subjects with a severe chronic disease or other clinically significant medical or psychological condition who are considered by the Investigator to be ineligible for the study.
15. Subjects who are pregnant or lactating at the day of screening.
16. Subjects who are planned to participate in another clinical trial during the present trial period.