From the New York Times:
Signaling the retreat of a childhood rite of passage, the incidence of chickenpox in the United States fell by 80 percent from 2000 to 2010, the Centers for Disease Control and Prevention reported last week.
The decline results from widespread use of the chickenpox vaccine, researchers said.
From 2000 to 2005, a period when a single dose of vaccine was recommended for children 12 to 18 months old and for older unvaccinated children, cases fell by 43 percent. The decline steepened once a second dose was recommended in 2006, with incidence falling 72 percent in the second half of the decade.