Cost-effectiveness and health impact of gender-neutral and single-dose HPV vaccination in Hong Kong

BackgroundSince 2019, Hong Kong has implemented a routine nonavalent human papillomavirus (HPV) vaccination program for schoolgirls aged 10-12 years with two-dose uptake of over 85%. However, the impacts of gender-neutral vaccination (GNV) with a single-dose schedule have not been studied. ObjectiveTo evaluate the cost-effectiveness of expanding the two-dose female-only vaccination (2dFOV) to GNV and reducing the schedule to one dose. MethodsWe modeled the impacts of HPV vaccination on the burden of HPV-related cancers in both genders at various vaccine uptake among schoolboys. We estimated the changes in the associated costs and health benefits across the lifetime of all cohorts of both genders over a time horizon of 100 years with a 3% annual discount rate. We calculated the incremental cost-effectiveness ratio (ICER) of expanding 2dFOV to GNV, using a two-dose or one-dose schedule compared to a threshold of one gross domestic product per capita (US$48,757). Sensitivity analyses were performed to assess the uncertainty of the findings. ResultsAssuming base case vaccination cost and 85% uptake for both genders, two-dose GNV (2F2M) has an ICER of US$109,375 (90% prediction interval: (US$63,824, US$264,980)) compared to 2dFOV and is not cost-effective. Compared to 2dFOV under the same assumptions, giving one dose to both genders (1F1M) always results in QALY gains if one-dose schedule provides 30-year protection; this strategy is cost-effective (and may be cost-saving). If the one-dose schedule gives only 20-year protection, 1F1M incurs QALY gains in 91% and 67% of simulations if boys uptake is 85% and 50%, respectively. Compared to 2dFOV, if 85% of boys are vaccinated and one-dose schedule provides at least 20 years of protection, adding one dose for boys (2F1M) is cost-effective in 47% of simulations at the base case vaccination cost. Conclusions1F1M is more effective than 2dFOV if it protects for at least 20-30 years with boys uptake of 50% or above. The findings highlight the potential of implementing GNV with a single-dose schedule for better resource allocation and optimizing the impacts of the vaccination program.