Gardasil, also known as Gardisil or Silgard or recombinant human papillomavirus vaccine [types 6, 11, 16, 18], is a vaccine for use in the prevention of certain strains of human papillomavirus (HPV), specifically HPV types 6, 11, 16 and 18. HPV types 16 and 18 cause an estimated 70% of cervical cancers, and are responsible for most HPV-induced anal, vulvar, vaginal, and penile cancer cases. HPV types 6 and 11 cause an estimated 90% of genital warts cases. Though it does not treat existing infection, vaccination is still recommended for HPV positive individuals, as it may protect against one or more different strains of the disease. The HPV strains that Gardasil protects against are sexually transmitted. It was approved in the US on June 8, 2006 by the U.S. Food and Drug Administration (FDA). In 2008, Gardasil was approved in 41 of U.S. states. The Gardasil vaccine has also been approved in 120 other countries. The FDA recommends vaccination before adolescence and potential sexual activity.