Evaluate the Safety and Immunogenicity After MG1111(BARICELA Inj.) as 2nd Vaccination in 4 ~ 6 Year Old Healthy Children With a History of 1st Varicella Vaccination

* Primary objective is to assess the safety of MG1111 until Day 42 using as 2nd vaccination
* Secondary objective to assess the immunogenicity and safety of MG1111 using as 2nd vaccination

1. Safety

   * Incidence of fever (temperature ≥39.0℃) within 42 days after the IP administration
   * Incidence of fever (temperature ≥39.0℃) within 7 days after the IP administration
   * Solicited local/systemic AEs occurred within 7 days after the IP administration
   * Unsolicited adverse events that occurred within 42 days after the IP administration
   * Serious adverse events that occurred within 1 year after the IP administration
   * Vital signs and physical examinations
2. Efficacy (Immunogenicity)

   -GMT(Geometric Mean Titer) and GMR(Geometric Mean Ratio(fold change))measured by the glycoprotein enzyme-linked immunosorbent assay (gpELISA) at before and 42 days after the IP administration
3. Exploratory assessment

   * GMV and GMR of VZV-CMI response measured by INF-r ELISPOT at before and 42 days after the IP administration
   * GMT and GMR of the antibody titer measured by gpELISA at before and after the IP administration for 3 years
   * Varicella-like rash and Varicella-zoster virus genotyping analysis occurred after IP administration for 3 years

Eligibility Criteria:
Inclusion Criteria:

* Healthy children between 4 and 6 years of age as of the date of written consent
* Subjects who have a history of 1st Varicella vaccination at least 3 years ago from the administration of investigational product
* Subjects or parent/legal representative willing to provide written informed consent and able to comply with the study requirements
* Negative history of Varicella infection

Exclusion Criteria:

* Subjects with a history of exposure to varicella through contact with a varicella patient at home, school, or childcare facility within 4 weeks before the administration of investigational drug
* Subjects who have a history 2 times or more of varicella vaccine injections
* Subjects who had an acute febrile (at least 38.0 ℃) episode at some time during the 72 hours before the administration of investigational product
* Subjects who had any suspected allergy symptoms including systemic rash during the 72 hours before the administration of investigational product
* Subjects with a history of Guillain-Barre syndrome.
* Subjects with a severe chronic disease and considered ineligible for the study at Investigator's discretion
* Subjects with a history of hypersensitivity to any ingredient such as gelatin, antibiotics (Neomycin, Kanamycin, Erythromycin)
* Active tuberculosis patient
* Subjects who had received other vaccinations within 4 weeks before the administration of investigational product
* Subjects with immunodeficiency history
* Subjects who had received salicylates (aspirin, bismuth, subsalicylates) within 4 weeks before the administration of investigational drug
* Subjects who administered immune globulin, gamma globulin, or blood products such as whole blood within 44 weeks before the administration of investigational drug
* Subjects who had received immunosuppressant or immune modifying drug within 12 weeks before the administration of investigational drug
* A. Azathioprine, Cyclosporin, Interferon, G-CSF, Tacrolimus, Everolimus, Sirolimus, etc.
* B. Subjects who administered high dose of corticosteroids (greater than 2 mg/kg/day in case of under 10kg subjects or ≥20mg/day in case of above 10kg subject of prednisone for 14 days) (However, inhaled, intranasal, topical corticosteroids administration in allowed)
* Subjects who administered anti-viral drug within 4 weeks before the administration of investigational drug
* Subjects who have participated in any other clinical trials within 24 weeks of the administration of the investigational product
* Subjects with other clinically significant medical or psychological condition who are considered by the Investigator to be ineligible for the study