Human Papilloma virus (HPV) are viruses that cause a common infection of the skin and genitals in men and women. Several types of HPV infection are transmitted by sexual activity and, in women, can infect the cervix (part of the uterus or womb). This infection often goes away by itself, but if it does not go away (this is called persistent infection), it can lead in women over a long period of time to cancer of the cervix. If a woman is not infected by HPV, it is very unlikely that she will get cervical cancer. This study will evaluate the efficacy of GSK Biologicals HPV 16/18 VLP/AS04 vaccine to prevent infection associated cervical pre-cancer and vaccine with HPV 16 or 18 and the vaccine safety, over 48 months, in young adolescents and women of 15/25 years of age at study start. Approximately 18.000 study subjects will either receive the HPV vaccine or a control vaccine (hepatitis A vaccine) administered intramuscularly according to a 0-1-6 month schedule.