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

Conditions: Varicella

Summary: * 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