Human papillomavirus (HPV) vaccines: a Canadian update.

A common sexually transmitted infection, human papillomavirus (HPV) has been linked to the development of cervical, anogenital, and head and neck cancers and genital warts. (2) Several randomized controlled trials have explored the efficacy and safety of two vaccines for primary prevention of infection by HPV types 16 and 18, those most commonly implicated in the development of cervical cancer. (3) An HPV vaccine, Gardasil, was approved in Canada in 2006, and a second vaccine, Cervarix, is undergoing Health Canada review. (4) Some unresolved questions about HPV vaccinations relate to the ideal age for immunization, duration of effect, immunization of women already infected, vaccination of males, implications for Papanicolaou (Pap) smear programs, barriers to uptake, need for monitoring and registries, cost effectiveness, and programs to ensure access for special populations.