Females: 11 or 12 years of age. This age group has the best response to the vaccine, and the vaccine must be given before sexual activity begins. HPV vaccine can be started at 9 years. It is also recommended for females aged 13 through 26 years who have not been vaccinated or did not finish the 3-shot series. Females and males: 11 or 12 years of age. This age group has the best response to the vaccine, and the vaccine must be given before sexual activity begins.  Females and males: 11 or 12 years of age. This age group has the best response to the vaccine, and the vaccine must be given before sexual activity begins.  It is recommended for males aged 13 through 21 years who have not been vaccinated or did not finish the 3-shot series.