EXPANDING THE NORWEGIAN HPV VACCINE PROGRAM TO INCLUDE BOYS

Purpose: Increasingly, countries have introduced vaccination against human papillomavirus (HPV), causally linked to several cancers and genital warts, targeted to young girls, but few have recommended routine vaccination of boys. Declining vaccine prices and the growing evidence of vaccine impact on reducing HPV-related conditions in both women and men prompts countries, such as Norway, to decide whether HPV vaccination of boys is warranted.

Method: A previously-published dynamic model of HPV transmission was updated to integrate recent evidence of gender- and type-specific natural history of HPV infections and empirically calibrated to observed HPV prevalence and cervical cancer incidence in Norway. Reductions in the incidence of HPV, which include both the direct and indirect benefits of vaccination, were applied to a microsimulation model of the natural history of cervical cancer in the presence of status quo screening, and to incidence-based models for other non-cervical HPV-related diseases among both men and women. We adopted a societal perspective and compared the incremental costs and benefits (discounted 4% annually) of a scenario reflecting the current 3-dose coverage level of pre-adolescent girls (75%) with and without similar coverage in boys in a school-based delivery program. Multiple good-fitting parameter sets from the dynamic model were used to explore the impact of parameter uncertainty on reductions in HPV incidence. Sensitivity analyses were conducted on vaccine cost and properties, and differential uptake among boys.

Result: Assuming 75% vaccine coverage, high, lifelong vaccine efficacy, and the current market price of the vaccine (plus administration and supplies), we found that expanding the vaccination program to include boys generally exceeded the commonly cited willingness-to-pay threshold in Norway (i.e., $83,000/QALY), compared with vaccination of 12-year-old girls alone, even when including vaccine benefits to all HPV-related conditions. However, the current tender price is estimated at half the market price (not-publicly available); under this assumption, vaccinating both girls and boys exceeded $100,000/QALY when only cervical cancer endpoints were considered but fell below Norway’s willingness-to-pay threshold when including all HPV-related conditions. Results remained stable when male uptake was 50%.

Conclusion: At Norway’s current market price, expanding the HPV vaccination program to boys is unlikely to be cost effective; however, at the assumed tender price, vaccinating boys becomes more attractive and may warrant a change in the current female-only vaccination policy.