The impact of human papillomavirus (HPV)-16/18 vaccination on the incidence of infection and disease can be explored in a range of different models. Here we explore the epidemiological and economic impact of vaccination where screening is absent and where it is well established. The importance for epidemiology of assumptions about naturally-acquired immunity and heterogeneity in risk behaviours are highlighted, as are the importance for health economic outcomes of vaccine costs and the ability to modify screening strategies. To date, model results are consistent in predicting a useful role for vaccine, but further epidemiological data are required to help test the validity of models.