Chickenpox cases in the United States sank almost 80% between 2000 and 2010 in 31 states, with the help of Merck's ($MRK) varicella vaccine. The CDC published the findings Aug. 17 in the organization's Morbidity and Mortality Weekly Report. The findings show a two-dose round of the vaccine--recommended for children in 2006--caused cases of chickenpox to decline 70% over the course of four years.
Merck has the chickenpox vaccine market cornered in the U.S. There are two chickenpox vaccines licensed in the nation, according to the Centers for Disease Control and Prevention, both made by Merck: Varivax and ProQuad. ProQuad is a combination measles, mumps, rubella and varicella vaccine that the company plans to roll out in the U.S. in October. Varivax, however, is already on the market. In 2011, total sales for the vaccine hit $902 million, according to data from EvaluatePharma. For ProQuad, worldwide sales were at $70 million last year.
CDC figures show the biggest drop in chickenpox cases occurred in children ages 5 to 9. The varicella vaccine made it into the rotation of childhood shots in 1996 and a second dose was recommended in 2006. That second dose helped cut chickenpox incidence 72% from 2006 to 2010.
Chickenpox, an uncomfortable and sometimes serious disease, causes a blister-like rash, itching, tiredness and fever. Before a vaccine entered the picture, about 4 million people in the U.S. came down with the disease each year.