Most of the developed countries, including the Netherlands, have adopted a national HPV immunization program for girls. However, the number of preadolescent girls in the Netherlands who have completed the full vaccine series has plateaued around 58-60%. We examined the relative health impact of vaccinating boys in comparison to increasing the HPV vaccination coverage among girls, and performed a cost-effectiveness analysis of a sex-neutral vaccination plan.
We expanded a Bayesian synthesis framework, previously employed to estimate the benefits in the burden of the HPV 16 and 18-related disease in men following a gender-neutral vaccination campaign (Bogaards et al BMJ 2015). Our model considered the full spectrum of the HPV related cancers in males and females and accounted for the herd immunity effect deriving from female and male vaccination. We explicitly distinguished the benefit in the male homosexual population from that in the heterosexual population. We assumed a 98% vaccine efficacy and lifelong protection against HPV 16 and 18-related disease. In the cost-effectiveness analysis we investigated whether vaccinating 40% of the boys is a good-value-for-money strategy in addition to the current vaccination coverage of 60% among girls. Costs and effects were discounted by 3%, the cost-effectiveness threshold was set equal to the gross domestic product per capita, and a health-care-decision-maker perspective was taken.
We observed that vaccinating 40% of the boys yields the same gain in life-years as increasing the uptake in girls from 60 to 80%. Vaccinating 40% of boys in addition to 60% of girls gained an additional 5.2 life-years per thousand girls and 5.8 life-years per thousand boys. Prevention of cervical disease accounted for 73% of the life-year gain in girls, and 67% of the gain in boys was due to prevention of oropharyngeal cancers. Adding 40% uptake among boys was cost-effective, even at high total vaccination cost of 200-300 euros per vaccinated boy. If we would have excluded oropharyngeal cancer from our calculations, vaccinating boys would be cost-effective at vaccination costs of 100-150 euros, which seems achievable at current low HPV vaccine tender prices.
Vaccinating boys is likely to be a cost-effective alternative if the uptake among girls remains at the current level of 60%.
Bogaards, J. A., Wallinga, J., Brakenhoff, R. H., Meijer, C. J., & Berkhof, J. (2015). Direct benefit of vaccinating boys along with girls against oncogenic human papillomavirus: bayesian evidence synthesis. bmj, 350, h2016.