Safety Study of a Refrigerator-stable Formulation of VARIVAX®

Inclusion Criteria: 1. Healthy infants from 12 months of age to 15 months of age. 2. Consent form signed by both parents or by the legal representative(s), properly informed about the study, 3. Parent(s) able to understand the protocol requirements and to fill in the Diary Card. Exclusion Criteria: 1. Prior receipt of measles, mumps, rubella or varicella vaccine either alone or in combination vaccine, 2. Known or suspected clinical history of infection with measles, mumps, rubella, varicella or zoster, 3. Any known recent (≤30 days) exposure to measles, mumps or rubella, 4. Any known recent (≤30 days) exposure to varicella or zoster involving: 5. Any recent (≤3 days) history of febrile illness (rectal temperature ≥38.0°C), 6. Active untreated tuberculosis, 7. Any known blood dyscrasia, leukemia, lymphomas of any type, or other malignant neoplasms affecting the bone marrow or lymphatic systems, 8. Any immune impairment or humoral/cellular deficiency, neoplastic disease or depressed immunity, 9. Any previous (≤150 days) receipt of immune serum globulin or any blood-derived products or scheduled to be administered through visit 3, 10. Any recent receipt of an inactivated or a live vaccine (≤ 30 days) or scheduled vaccination through visit 3