Is cervical cancer vaccine effective?

There is no vaccine to prevent cervical cancer per se. Vaccines are meant to prevent infection with Human Papilloma Virus (HPV), which can, among other factors, cause cervical cancer. However it must be kept in mind that all causes (such as ethnic, racial, environmental, genetic etc.) of cervical cancer are not known and hence vaccination cannot prevent all cancers. There are many strains of HPV virus. One vaccine (Gardasil) is claimed to prevent infection with four strains called HPV 6, 11, 16 and 18. In other words, a vaccinated person can still get infected with strains other than 6, 11, 16 and 18. Another vaccine (Cervarix) is claimed to prevent HPV strains 16 and 18. Thus strains other than 16 and 18 can still infect the vaccinated person.