HPV疫苗用於男性不符合成本效益
作者：Zosia Chustecka
出處：WebMD醫學新聞
October 12, 2009 —10月8日線上發表的英國醫學期刊(British Medical Journal)中的新分析與編輯評論結論表示，除了女孩之外，讓男孩也接種人類乳突病毒(HPV)疫苗不符成本效益。
在許多國家已經進行女孩預防子宮頸癌的疫苗接種。約有70%的子宮頸癌是由HPV第16和第18型引起，目前有兩種疫苗：Gardasil (Merck Co藥廠)與Cervarix (GlaxoSmithKline藥廠)。
之前的研究一致顯示，HPV疫苗對青春期前(12歲)女孩有符合成本效益，麻塞諸塞州波士頓哈佛公共衛生學院健康決策科學中心健康政策與管理系的Jane Kim博士與Sue Goldie醫師等作者指出，新研究也是如此。
有人提出對男孩施打疫苗，以預防生殖器疣的提議。大約90%的生殖器疣是由HPV第6型和第11型所引起，只有Gardasil這項產品含有這兩項。另外也有人認為，男孩接種疫苗可以改善群體免疫效應。
在美國，如Medscape Oncology最近報導的，美國食品藥物管理局諮詢委員會最近建議核准使用Gardasil於男孩以預防生殖器疣。
不過，新分析的結論認為，相較於只有女孩的疫苗計畫，將男孩納入HPV疫苗計畫可能無法提供適當價值，而且浪費資源。
【任何情況都不符合成本效益】
研究者使用疾病模擬模式來處理美國流行病學、臨床與經濟面的資料。將不同組的資料輸入該模式後，他們可以設定各種情境，例如疫苗吸收高低、疫苗保護期較長或較短等。
三篇中有其他兩篇成本效益分析獲得類似結論。編輯評論指出，提出截然不同的結論的第三篇研究，實際上獲得由Gardasil的製造商藥廠Merck Co的支持(Emerg Infect Dis 2007;13:28-41)。
編輯評論作者是國家癌症研究中心癌症流行病學與基因學小組的Philip Castle博士，以及阿拉巴馬大學預防醫學小組的Isabel Scarinci博士。
編輯們解釋，只有在最有利的假定下，在女性之外增加男性使用HPV疫苗好處的成本會低於每QALY [生活品質-年]需要$100,000，只有低於這個閾值才會被視為好的經濟投資。
他們指出，基於降低健康照護花費以及增加效果的需要，沒有任何情境可以讓納入男性的HPV疫苗計畫費用低於每QALY需要$50,000，這是比較符合財政的閾值。
編輯指出，不論何種模式，經比較，12歲女孩施打HPV疫苗一定是個好的健康投資。
編輯們寫道，用來產生成本效益的估計模式，因為HPV相關疾病來源的不確定性而有其限制。不過，相較於兩性的疫苗接種情況，女性施打HPV疫苗的相對助益，不太可能和這些模式有太大差異，對健康的影響是清楚的：女性有良好的疫苗覆蓋就不需要對男孩施打疫苗。
編輯提到另外一點，大部份的子宮頸癌(>80%)發生在已開發國家以及無法負擔HPV疫苗的資源不足區域。針對這些族群的年輕女性進行HPV疫苗接種，且篩選年長婦女，對於降低子宮頸癌的發生，將會比在資源豐富地區讓年輕男性施打疫苗有更大的效果。
作者們和編輯們都宣告沒有相關財務關係。
HPV Vaccination of Males Not Cost-Effective
By Zosia Chustecka
Medscape Medical News
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.
BMJ.2009;339:b3884, b4127.
