A vaccine to prevent infection with HPV types 16 and 18, which are 2 types most commonly linked to cervical cancer, is recommended for girls and young women aged 11 to 26 years. However, many women have already been exposed to HPV by this age. Because the vaccine does not treat HPV, the value of the vaccine in older women is questionable. Still, the vaccine makers are trying to get the U.S. Food and Drug Administration to approve the vaccine for older women.