The HPV vaccine, Gardasil, protects against HPV types 16 and 18 (which cause 70% of cervical cancer) and 6 and 11 (which cause 90% of genital warts). It is most effective when given before a person becomes sexually active. In clinical trials, the vaccine was 99% effective in preventing cervical dysplasia and 93% effective in preventing genital warts among females who were not yet sexually active. Among females who were already sexually active (and may have already been exposed to HPV), the vaccine was only 40% effective in preventing cervical dysplasia and 68% effective in preventing genital warts. The vaccine has been officially approved for females and males ages 9-26. It is very important for vaccinated females to still get Pap tests regularly, as they will not be protected against the HPV types that cause 30% of cervical cancer.
A second HPV vaccine, Cervarix, has been approved for use in females. Cervarix protects against HPV types 16 and 18 only. This vaccine is available to females ages 9 to 25 years of age. Cervarix is administered in 3 shots over a 6 month period of time. While Cervarix has been found to be up to 99% effective in preventing the 2 main HPV types that lead to cervical cancer, it is only effective for a little more than 4 years and may need to be re-administered to provide continued protection.