Human Papillomavirus: Over 100 HPVs are known, and ~30 are typically transmitted sexually. An estimated 80% of sexually active adults have one or more strains without knowing it. HPV types 16 and 18 are responsible for >70% of cervical cancer cases. However, most HPV infections are cleared rapidly by the immune system and do not progress to cervical cancer. Some HPVs, such as types 6 and 11, can cause genital warts. Other skin warts are caused by type 1 HPV. Recent studies have concluded that condoms only offer limited protection against transmission of genital HPVs, since HPVs can infect genital skin areas not covered by condoms.
On June 8th, 2006, the FDA approved Gardasil, an HPV vaccine that protects women against initial infection with HPV types 16 and 18, and types 6 and 11.