[Human papillomavirus (HPV) vaccines]

In the last 15 years, fifteen of the human papillomaviruses (HPVs) that infect the genital tract have been recognized as the etiological agents of cervical cancer. Cervical cancer is thus a cancer that could be prevented by immuniza- tion. The recently licensed HPV subunit vaccine and the availability of another prophylactic vaccine in the near future for types 16 and 18 make this a realizable goal. The safety, immunogenicity and efficacy demonstrated for two vaccines are very promising. Phase I and phase II clinical trials have determined the tolerance, immunogenicity, dose and schedule of injections and phase IIb and phase III clinical trials have demonstrated the high efficacy of these vaccines. More than 80 % protection against incident infections was observed and close to 100 % protection was observed against persistent infections associated with cervical lesions. Anti-HPV antibodies persisted for 4-5 years, with antibody titers 5 to 17 times higher than observed in control subjects with anti-HPV antibodies ac- quired after natural infection. However, there are still some unresolved questions such as duration of protection, need for booster dose, protective level of anti-HPV antibodies, and whether there is protection against infection with HPV types closely related to HPV-16 and HPV-18 but not incorporated in the vac- cines. For a maximum efficacy, papillomavirus vaccines must be administered to pre-adolescents and adolescents before the beginning of sexual activity. Vaccine coverage and hence the overall efficacy of vaccination against HPV will depend on public health policies, social attitudes and cost of the vaccines. HPV immu- nization should significantly reduce the incidence of cervical cancers in 10 to 30 years, and should reduce the number of treatments due to a significant reduction in precancerous lesions in the shorter term. These vaccines also have the potential to reduce the incidence of other cancers such as anal, vulval, vaginal, and penial cancers for which the HPV prevalence is lower or the association with HPV infection is weaker. HPV vaccination and screening of precancerous cervical lesions are complementary measures and the implementation of HPV vaccination is an opportunity to strengthen the health policies for prevention of cervical cancer.