In 2011, an advisory panel for the Centers for Disease Control and Prevention (CDC) recommended the vaccine for boys ages 11–12. This was intended to prevent genital warts and anal cancers in males, and possibly prevent head and neck cancer (though the vaccine's effectiveness against head and neck cancers has not yet been proven). The committee also made the vaccination recommendation for males 13 to 21 years who have not been vaccinated previously or who have not completed the three-dose series. For those under the age of 27 who have not been fully vaccinated the CDC recommends vaccination.