October 12, 2009 — Vaccinating boys against human papillomavirus (HPV) in addition to girls is not likely to be cost-effective, conclude a new analysis and an accompanying editorial published online October 8 in the British Medical Journal.
Vaccination of girls is already underway in many countries to protect against cervical cancer. Around 70% of cervical cancer is caused by HPV types 16 and 18, and 2 vaccines protect against these: Gardasil (Merck Co) and Cervarix (GlaxoSmithKline).
Previous studies that have consistently shown that HPV vaccination of preadolescent (12-year-old) girls is cost-effective, and the new analysis agrees, note the authors, Jane Kim, PhD, and Sue Goldie, MD, MPH, from the Department of Health Policy and Management at the Center for Health Decision Science at the Harvard School of Public Health in Boston, Massachusetts.
Vaccination of boys has been proposed to protect against genital warts. Around 90% of genital warts are caused by HPV types 6 and 11, and only Gardasil offers protection against these. There is also an argument that vaccinating boys will improve "herd immunity."
In the United States, this use of Gardasil — i.e., vaccinating boys to protect against genital warts — was recently recommended for approval by a US Food and Drug Administration Advisory Committee, as reported by Medscape Oncology.
However, the new analysis concludes that "including boys in an HPV vaccination program is unlikely to provide good value for resources, compared with vaccinating girls only."
Not Cost-Effective Under Any Scenario
The researchers used a disease-simulation model to process epidemiologic, clinical, and economic data from the United States. By inputting different sets of data into the model, they could envisage various different scenarios, such as the high and low uptake of the vaccine and shorter and longer duration of vaccine protection.
A similar conclusion was reached by 2 other cost-effectiveness analyses, by not a by third. The study that drew contrasting conclusions was supported by Merck Co (Emerg Infect Dis 2007;13:28-41), manufacturer of Gardasil, notes an accompanying editorial.
The editorial was authored by Philip Castle, PhD, MPH, from the Division of Cancer Epidemiology and Genetics at the National Cancer Institute in Bethesda, Maryland, and Isabel Scarinci, PhD, from the Division of Preventive Medicine at the University of Alabama in Birmingham.
"Only under the most favorable assumptions for the benefits of adding male HPV vaccination to female vaccination did the cost fall below $100,000 per QALY [quality of life-year], the threshold below which an intervention is considered a good economic investment," the editorialist explain.
Under no scenario did the cost of including males in HPV vaccination programs fall below $50,000 per QALY, which is perhaps a "more fiscally responsible threshold, given the need to lower healthcare costs and increase efficiency," they add.
"By comparison, HPV vaccination of 12-year-old girls was always a good health investment," whatever the modeling, the editorial notes.
Good coverage of females obviates the need to vaccinate boys.
"Models used to generate cost-effectiveness projections have limitations imposed by the uncertainties about the course of HPV-related disease," the editorialists write. "Nevertheless, the relative benefits of HPV vaccination of females, compared with vaccination of both sexes, is unlikely to differ greatly with fine tuning of the models, and the health implications are clear — good coverage of females obviates the need to vaccinate boys."
The editorialists make one other point. The majority of cervical cancer (>80%) occurs in developing countries and in areas of low resources, which cannot afford or access HPV vaccines. "Targeting young women in these populations for HPV vaccination and screening older women would have a bigger effect on reducing the burden of cervical cancer than widespread vaccination of young men from resource-rich areas," they state.
The authors and editorialists have disclosed no relevant financial relationships.
