human papilloma virus

Can a girl get vaccinated against HPV even if she's already sexually active?

Anonymous
asks:
One of the ways to help prevent cervical cancer and/or HPV infection is by taking a vaccination with HPV vaccine. I read it somewhere and it says that ideally females should get the vaccine before they are sexually active. This is because the vaccine is most effective in women/girls who have not yet acquired any of the HPV types covered by the vaccine....