http://www.cancer.gov/Templates/doc.aspx?viewid=31799A1E-2B27-4184-9264-A60AD9A1A054

Key Points

Human papillomaviruses (HPV) are a group of more than 100 viruses. Certain types of HPV are the major cause of cervical cancer (see Questions 1 and 2).
The U.S. Food and Drug Administration (FDA) approved a vaccine that is highly effective in preventing infection with some types of HPV (see Question 3).
Complete vaccination has the potential to reduce cervical cancer deaths around the world by as much as two-thirds (see Question 7).
The vaccines are proven to be effective only if given before an individual is infected with HPV (see Question 11).
It is important for both vaccinated and unvaccinated women to continue to undergo cervical cancer screening (see Questions 4 and 14).