HPV vaccine has not shown to increase teen girls sexual activity or to engage in riskier sexual practices.

The researchers examined two risk perceptions: did the participants feel they still needed to practice safer sex after the HPV vaccine and did the participants feel like the vaccine protected then against other sexually transmitted infections (STIs) besides HPV.
The study showed that the vast majority thought it was still important to practice safer sex after vaccination, and most did not believe that HPV vaccination protected against other STIs. This does give us convincing evidence that vaccination does not lead to riskier behaviors—which should be reassuring to parents.
For background, HPV, human papillomavirus, is a sexually transmitted infection that is easily spread by skin-to-skin contact during sexual activity with another person. There are more than 40 types of HPV that can infect the genital areas or males and females. These HPV types can also infect the throat and mouth (and cause oral cancers). The HPV vaccines can protect against some of the most common types of HPV, including those that cause 70% of cervical cancers.
The HPV vaccine is suggested by the U.S. Advisory Committee of Immunization practices to females between ages 11 and 26, to males between 11 and 21, and additionally to men aged 22 to 26 who are at “high risk for HPV.”