肺炎鏈球菌接合性疫苗之經濟評估

Abstract

背景: 台灣現有兩種不同設計之新型肺炎鏈球菌接合性疫苗能有效預防肺炎鏈球菌相關疾病，全國新生兒公費肺炎鏈球菌接種計劃審議中，惟缺乏適當之疫苗經濟評估。 目的 藉由「成本效果分析」評估於新生兒全面接種不同之新型肺炎鏈球菌接合性疫苗(PCV10及PCV13)對國內肺炎鏈球菌感染相關疾病的影響。. 方法 使用馬可夫決策分析建構經濟評估模型藉以評估三種不同的疫苗接種策略：「不施打新型肺炎鏈球菌接合性疫苗」、「全面接種PCV10疫苗」以及「全面接種PCV13疫苗」。 本研究使用「全人口」模型進行分析以符合實際施打疫苗之情境。並藉由健保資料庫及已發表之相關文獻蒐集國內肺炎鏈球菌感染相關疾病各種的參數，如不同的肺炎鏈球菌疾病(侵襲性肺炎鏈球菌感染、中耳炎及肺炎)的國人發病率、疾病相關的合併症以及後遺症、疫苗價格、疫苗保護效果及群體免疫力、直接以及間接醫療成本等等進行「成本效果分析」。在進行完「基本案例分析」後，我們再使用「敏感度分析」、「機率性敏感度分析」以及「情境模擬分析」等方式測試初步分析後所得結果的證據強度，同時分析其他替代性疫苗接種政策之成本效果比，以期求得客觀的分析結果。. 結果 由「全人口」模型進行分析，發現在「成本效果分析」方面顯示相較於「接種PCV10 疫苗」或「完全不接種疫苗」兩種策略而言，「全面接種PCV13疫苗」為最具經濟效益之疫苗接種政策，且其成本效果分析結論為「節省成本」的。而「敏感度分析」的結果顯示「折現率」，「單純性肺炎住院的間接成本」，「接合性疫苗對肺炎及中耳炎的群體免疫力」等三種變相為最重要之影響因子。而在「機率性敏感度分析」分析則發現即便考量及變動各種因子的分布，其結果仍顯示為「全面接種PCV13疫苗」為最具經濟效益的策略。而「情境模擬分析」結果則顯示除全面嬰兒疫苗接種之外，即便是在一歲及兩歲孩童追加接種疫苗，其成本效益分析仍顯示「全面接種PCV13」 為最為「節省成本」之預防接種策略。 結論 由「全人口」模型之「成本效果分析」可知，「全面接種PCV13疫苗」為一具「節省成本」效果之健康政策。即便除了出生嬰兒外，擴大於5歲以下幼兒全面進行補接種仍為一極具經濟效益之政策。為涵蓋抗藥性之肺炎鏈球菌19A血清型菌株及依據本經濟評估之結果，「全面接種PCV13」應為新型肺炎鏈球菌接合性疫苗之優先選擇。預期本論文經濟評估的結果能為衛生政策制定者提供科學上的證據，協助其決定全面嬰幼兒接種新型肺炎鏈球菌接合性疫苗時的決策參考。

Background Two newly designed pneumococcal conjugate vaccines are scheduled included in nationwide immunization program in Taiwan. However, evidence from cost-effectiveness analysis is still poorly understood. Objectives To investigate the impact of universal immunization (PCV10 & PCV13) on both health and economic outcomes of pneumococcal diseases in Taiwan. Methods We designed a Markov decision analytic model to investigate three vaccination strategies: no vaccination, universally vaccinated with PCV10 and PCV13. Both population cohort and birth cohort models were simulated. The parameters, such as incidences of various pneumococcal diseases, disease specific complications and sequelaes, vaccine cost, vaccine efficacy and herd immunity, direct and indirect medical costs in Taiwan were assigned for base-case simulation. Sensitivity analysis, probabilistic analysis and scenario analysis were performed for testing the robustness of our conclusion. Results With population model, the CEA result showed PCV13 dominated both PCV10 and no vaccination, and was “cost saving”. Univariate sensitivity analysis showed the discount rate, herd immunity of PCV13 for simple pneumococcal pneumonia admission, indirect cost of pneumococcal admission and outpatients are most influential parameters. The probabilistic analysis also showed PCV13, when compared with both PCV10 and no vaccination strategy, was “cost-saving” after considering the uncertainty of variables. The “PCV13 vaccination for infants with catch-up program of children under the age of 5 years” is as “cost-saving” as the infantile vaccination program of PCV13. Conclusion The cost–effectiveness study of universal immunization of infants with PCV 13, even with extended vaccine coverage for children aged 1-4 years, is “cost saving” when compared with universal PCV10 immunization and no vaccination. Both the necessity of extending vaccine coverage of 19A and the cost-saving result of this study urged the commencement of universal infantile vaccination with PCV13. The results of this dissertation provide scientific evidence for health policy makers on deciding new PCV strategies for universal immunization for infants in Taiwan.