The purpose of this study is to check the safety and effectiveness of an investigational Measles, Mumps, Rubella, and chickenpox vaccine. This is a six-month study, including three office visits and two phone call follow-ups. Qualified participants may be compensated $120 per visit for time and travel. Your child may be able to qualify for this study if they:

Are 4-6 years of age

Are in good health

Have received single (first) doses of a measles, mumps, rubella, and chickenpox vaccine when they were between 1–2 years of age