This question asks you to use the data presented in the graph to support a given conclusion about a vaccine and its relationship to chicken pox.
Varicella is a virus that causes the disease chicken pox. Medications are used to treat the symptoms of fever and discomfort associated with chicken pox. In 1995, a varicella vaccine was made available to people in the United States.
The graph shows the number of chicken pox cases reported in four U.S. states from 1991 to 2007.