Mathematical modelling of cervical cancer vaccination in the UK

Human papillomaviruses (HPV) are responsible for causing cervical cancer and anogenital warts. The UK considered a national vaccine program introducing one of two licensed vaccines, Gardasil™ and Cervarix™. The impact of vaccination is, however, difficult to predict due to uncertainty about the prevalence of HPV infection, pattern of sexual partnerships, progression of cervical neoplasias, accuracy of screening as well as the duration of infectiousness and immunity. Dynamic models of HPV transmission, based upon about thousands of scenarios incorporating uncertainty in these processes, were developed to describe the infection spread and development of cervical neoplasia, cervical cancer (squamous cell and adenocarci-noma) and anogenital warts. Each scenario was then fitted to epidemiological data to estimate transmission probabilities and the best-fitting scenarios used to predict the impact of twelve different vaccination strategies. Our analysis provides relatively robust estimates of the impact of HPV vaccination, as multiple sources of uncertainty are explicitly included. The most influential remaining source of uncertainty is the duration of vaccine-induced protection.