Human papillomavirus vaccines versus cervical cancer screening.

Prophylactic vaccination with human papillomavirus (HPV) virus-like particle (VLP) vaccines against HPV 16 and HPV 18, which are the cause of 70% or more of cervical cancers in women, has transformed our prospects for reducing the incidence of this disease on a global scale. HPV VLP vaccines are immunogenic, well tolerated and show remarkable efficacy, achieving >98% protection in randomised clinical trials against the obligate precursor lesions cervical intraepithelial neoplasia grade 2/3 (CIN2/3) and adenocarcinoma in situ. The implementation of these vaccines as a public health intervention is, however, complex. Cervical cancer screening can be a highly effective secondary intervention, but in the developing world these programmes are either not available or are ineffective. HPV vaccination represents the most effective intervention in that scenario. In countries with successful well-organised cervical cancer screening programmes, such as the UK, the cost-effectiveness of vaccination as opposed to screening is a major factor. Screening will have to continue, as only two of the 15 oncogenic HPV types are in the vaccines and for two to three decades at least unvaccinated sexually active women will remain at risk for the disease. However, if both vaccination and screening are combined then the virtual elimination of cervical cancer and the other HPV 16 and 18-associated cancers is possible.