(credit: Robyn Beck/AFP/Getty Images)

(credit: Robyn Beck/AFP/Getty Images)

Boston (CBSNEWS.COM) – Rates of HPV strains related to genital warts and some cancers have decreased 56 percent among American teen girls since a vaccine was introduced in 2006, the Centers for Disease Control and Prevention reported Wednesday.

The government health agency’s new study, which was published in the June issue of The Journal of Infectious Diseases, shows that rates of vaccine-type HPV prevalence dropped from 11.5 percent before the vaccine was introduced to 5 percent by 2010 for 14 to 19 year-old-girls.

Gov. Rick Perry in 2007 signed an order requiring Texas girls to be vaccinated against HPV. That order was later overturned.

“These are striking results,” CDC director Dr. Tom Frieden said on a conference call Wednesday. “I think they should be a wake-up call that we need to increase vaccination rates because we can protect the next generation of adolescents and girls against the cancer that is caused by HPV.”

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