Similar to many developed countries, vaccination against human papillomavirus (HPV) is provided only to girls in New Zealand and coverage is relatively low (47% in school-aged girls for dose 3). Some jurisdictions have already extended HPV vaccination to school-aged boys. Thus, exploration of the cost-utility of adding boys’ vaccination is relevant. We modeled the incremental health gain and costs for extending the current girls-only program to boys, intensifying the current girls-only program to achieve 73% coverage, and extension of the intensive program to boys.
A Markov macro-simulation model, which accounted for herd immunity, was developed for an annual cohort of 12-year-olds in 2011 and included the future health states of: cervical cancer, pre-cancer (CIN I to III), genital warts, and three other HPV-related cancers. In each state, health sector costs, including additional health costs from extra life, and quality-adjusted life-years (QALYs) were accumulated. The model included New Zealand data on cancer incidence and survival, and other cause mortality (all by sex, age, ethnicity and deprivation).
At an assumed local willingness-to-pay threshold of US$29,600, vaccination of 12-year-old boys to achieve the current coverage for girls would not be cost-effective, at US$61,400/QALY gained (95% UI $29,700 to $112,000; OECD purchasing power parities) compared to the current girls-only program, with an assumed vaccine cost of US$59 (NZ$113). This was dominated though by the intensified girls-only program; US$17,400/QALY gained (95% UI: dominant to $46,100). Adding boys to this intensified program was also not cost-effective; US$128,000/QALY gained, 95% UI: $61,900 to $247,000).
Vaccination of boys was not found to be cost-effective, even for additional scenarios with very low vaccine or program administration costs – only when combined vaccine and administration costs were NZ$125 or lower per dose was vaccination of boys cost-effective.
These results suggest that adding boys to the girls-only HPV vaccination program in New Zealand is highly unlikely to be cost-effective. In order for vaccination of males to become cost-effective in New Zealand, vaccine would need to be supplied at very low prices and administration costs would need to be minimised.