Cost-effectiveness of extending human papillomavirus (HPV) vaccination programmes to boys in Japan

Human papillomavirus (HPV) causes not only cervical cancer in women, but also other HPV-related cancers in both men and women. Currently, Japan runs a national immunisation programme for girls only, while some municipalities started to give subsidy for vaccinations for boys. Considerations of HPV vaccination being a nationally gender-neutral programme is a current topic in health policy arena that raises a question whether such an extension is justifiable in terms of cost-effectiveness. Cost-effectiveness analyses were conducted to evaluate the efficiency of extending HPV vaccination programme to boys. A decision tree model with Markov model was developed accounting for anal, oropharyngeal, and cervical cancers. The target cohort was 12-year-old boys and girls. It was assumed that boys would receive 3 doses 4-valent (B4v) or 2 dose 9-valent vaccine (B9v) and girls would receive two doses 9-valent vaccine (G9v). Incremental cost-effectiveness ratio (ICER) of B4vG9v vs. G9v and B9vG9v vs. G9v were estimated from payers' perspective. Transition probabilities, utility weights to estimate effectiveness in terms of quality-adjusted life year (QALY), and disease treatment costs were either estimated or extracted from the literature. Costs per vaccination was assumed at JPY12, 000/US80 and JPY20, 000/US133 for 4v and 9v vaccine, respectively. Annual discount rate for both costs and effectiveness were set at 3%. While both gender-neutral vaccination programmes reduced disease treatment costs, the reduction was not able to offset vaccination costs. ICERs of B4vG9v programmes ranged from JPY15, 954, 845 ~ JPY17, 116, 194/US106, 366 ~ US114, 108 per QALY gained; of B9vG9v programmes from JPY14, 606, 709 ~ JPY16, 022, 742/US97, 378 ~ US106, 818 per QALY gained, depending on the vaccine uptake rates. ICERs were all larger than the willingness-to-pay criterion (WTP = JPY5, 000, 000/US33, 333 per QALY gained) for vaccine. Regardless of the vaccine used, we found that extending HPV vaccination programme to boys was not cost-effective. • Cost-effectiveness of extending HPV vaccination programmes to boys in Japan was evaluated. • Boys were assumed to get 4- or 9-valent vaccine, while girls receive only 9-valent. • Markov model was developed accounting for anal, oropharyngeal, and cervical cancers. • Extending HPV vaccination to boys was not cost-effective, regardless of vaccine type.