Vials of the HPV vaccination drug Gardasil. Doctors and public health experts say the new version of the vaccine could protect more people against cancer. Matthew Busch for The Washington Post/Getty Images hide caption

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Matthew Busch for The Washington Post/Getty Images

University of Miami pediatrician Judith Schaechter gives a girl an HPV vaccination in 2011. Joe Raedle/Getty Images hide caption

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Joe Raedle/Getty Images