New research published on bmj.com today reports that if boys were included in human papillomavirus (HPV) vaccination programs of pre-adolescent girls, it would not be cost-effective. It is probable that the costs of vaccinating boys will outweigh the added health benefits.
It has been consistently exposed in prior studies that HPV vaccination of pre-adolescent (12 year-old) girls provides good value for money. The latest data from clinical trials also imply that HPV vaccination in males has elevated efficacy against vaccine-type infections and genital lesions. Since HPV infections are sexually transmitted, vaccinating boys will probably give direct health benefits to the boys themselves as well as indirect health benefits to their sexual partners by reducing HPV transmission. However, the cost-effectiveness remains uncertain.
In order to find out more, researchers from The Harvard School of Public Health in Boston conducted a cost-effectiveness analysis. They compared HPV vaccination of pre-adolescent girls alone with vaccination of both pre-adolescent girls and boys in the US.
Models considering the dynamics of HPV infection and cervical cancer screening strategies were used in the study. The objective was to predict the health benefits and economic costs of programs by combining epidemiological, clinical, and demographic information from the US population.
In addition, the authors examined how alternative scenarios might impact on cost-effectiveness. They used various assumptions regarding screening practice, vaccine efficacy in boys, duration of vaccine protection, and long-term impact on health outcomes not yet observed in clinical trials (for example anal and oral cancers).
Interventions were considered good value for money if they were less than cost-effectiveness values ranging from $50,000 to $100,000 per quality-adjusted life year (QALY).
The results indicated that HPV vaccination of pre-adolescent girls including continued screening in adulthood is good value for money. 75 percent vaccination coverage and lifelong vaccine protection, routine vaccination of 12-year-old girls was consistently found to be less than $50,000 per QALY gained, compared with screening alone.
However, the inclusion of boys in the routine vaccination program generally surpassed the higher cost-effectiveness threshold of $100,000 per QALY. This was the conclusion even when assuming high vaccine protection and health benefits.
The researchers estimated that vaccinating both boys and girls would only fall under the cost-effectiveness threshold of $100,000 per QALY. This would be the case under conditions of high, lifelong vaccine efficacy against all potential health benefits (including other anogenital and oral cancers, genital warts, and juvenile onset recurrent respiratory papillomatosis), or under assumptions of lower efficacy with lower coverage or vaccine costs.
The authors explain: “Our results suggest that if vaccine coverage and efficacy are high among pre-adolescent girls, including boys in an HPV program is unlikely to provide comparatively good value for resources.”
They write in conclusion: “As new data become available and new information emerges, assumptions and analyses will need to be iteratively revised to continue to inform policies with respect to HPV vaccination.”
In a complementary editorial, two US researchers remark: “The health economic implications are clear – good coverage of females obviates the need to vaccinate boys.”
In addition, they indicate that more than 80 percent of the 500,000 annual cases of cervical cancer occur in low resource settings and developing countries. These populations cannot afford or access HPV vaccines. Therefore offering HPV vaccination to young women in these populations and screening older women would have a better effect on reducing the burden of cervical cancer than widespread HPV vaccination of young men from resource rich areas, they comment.
They say in closing: “The best policy is to ensure that preadolescent females are vaccinated worldwide.”
“Cost effectiveness analysis of including boys in a human papillomavirus vaccination programme in the United States”
Jane J Kim, assistant professor Sue J Goldie, professor
BMJ 2009; 339:b3884
doi:10.1136/bmj.b3884
“Should HPV vaccine be given to men?”
Philip E Castle, investigator, Isabel Scarinci, associate professor
BMJ 2009;339:b4127
bmj.com
Written by Stephanie Brunner (B.A.)