The federal government recommended that 11-12-year-olds only get two doses of the human papillomavirus (HPV) vaccine at least six months apart, rather than the current guideline of three doses.

The Centers for Disease Control and Prevention said Wednesday that it still believes teens and young adults ages 15-26 years old who start the vaccination series later still need three doses. The vaccine is intended to protect against an HPV infection that can cause cancer. HPV is the most common sexually transmitted infection, according to the CDC.