Fig. 1

Overview of the data sources and the key steps of the modelling. To compare the impact and cost-effectiveness of one-dose versus two-dose vaccination in 188 countries, we adopted a hybrid approach. First, we synthesised the age-specific impact of HPV vaccines of three published transmission dynamic models—HSA, HPV-ADVISE, Harvard—from 10 model-country settings. Second, we derived the primary impact of vaccination using a static model (PRIME). Third, we extrapolated the primary and secondary effects to the remaining countries in the world. Fourth, we measured and compared population-level impact (e.g. cervical cancers averted, number of females needed to be vaccinated, threshold costs of the first and second dose of the vaccine) for three vaccine strategies: no HPV vaccination (the counterfactual), a one-dose HPV vaccination schedule in which we assume that one dose of the vaccine provides either a shorter duration of protection (20 or 30 years) or lower vaccine efficacy (i.e. 80%) compared to two doses, and a two-dose HPV vaccination schedule in which two doses of the vaccine provides lifetime protection