The potential additional benefits of the third dose occur among women and heterosexual men, who would also benefit from a two-dose girls-only strategy. However, adding boys to an selleck chemicals HPV vaccination programme

would extend benefits to MSM, who do not benefit from the herd effects of girls-only vaccination [55] and have a disproportionately high burden of HPV-related disease [56] and [57]. Hence, policy-makers may deem a two-dose girls & boys strategy worthwhile even though it is likely to be less cost-effective than a three-dose girls-only strategy. To our knowledge, no study has examined the cost-effectiveness of different HPV vaccination schedules. However, a previous comparative modelling analysis, using our model and one from England [58], examined the potential population-level impact of two- and three-dose girls-only HPV

UMI-77 cost vaccination. The conclusions of both models were similar when examining 40–80% vaccination coverage: the predicted added population-level effectiveness of a third dose at preventing cervical cancer is minimal if the duration of protection of two doses is at least 20–30 years. The results from the comparative analysis and the robustness of our conclusions to vaccine costs/dose and vaccination coverage (between 50–80%; see Fig. 3 and Supplementary Table 3), suggests that the main cost-effectiveness conclusions of this paper are likely to be generalisable to other high income countries

with HPV epidemiology, health care costs and cervical screening similar to England and Canada. However, our results should not be extrapolated to resource-poor settings due to differences in sexual behaviour and HPV epidemiology. A limitation of our analysis is the validity of data on the proportion of MSM in the population and the burden of disease within this population. However, even when the proportion of MSM was assumed to be high (7% vs. 3% in the base-case), vaccinating boys with two doses remained dominated by three-dose girls-only vaccination. A second limitation of the analysis is that our model assumes no herd-protection from girls-only vaccination Carnitine dehydrogenase to MSM. Herd-protection to MSM is only included in scenarios with male vaccination, potentially overestimating the impact of including boys in vaccination programmes. However, no herd-immunity has been observed in MSM following the introduction of girls-only HPV vaccination [59]. As recommended by good modelling practice, we conducted internal, between-model and external/predictive validation [60]. First, HPV-ADVISE was calibrated to highly-stratified Canadian data on sexual behaviour, natural history and cervical cancer screening (internal validation), and model predictions were performed using multiple good fitting parameter sets.