- 學位論文
原住民地區學童肝炎狀態調查:B型肝炎疫苗接種在台灣實施二十年後
Hepatitis status among schoolchildren in aboriginal area after twenty years of universal hepatitis B vaccination program in Taiwan
摘要
背景及目的： 台灣是肝炎感染的流行地區，一般大眾B型肝炎帶原率為15-20%，C型肝炎是1-2%，而原住民地區成人肝炎感染盛行率普遍高於城市地區。台灣自從實施全國性B型肝炎疫苗預防接種後，已大幅降低肝炎感染盛行率，而原住民地區學生肝炎感染是否如同成人般有高的比例，以及肝炎疫苗預防接種在原住民地區實施後的效益，需要更進一步的了解。 材料與方法： 從2004年11月到2006年10月，就讀於高雄縣桃源鄉、三民鄉、茂林鄉以及台東縣大武鄉原住民地區國小與國中學生一共1755人被邀請參與此次的研究，參與的學生接受問卷調查與血清學檢查；檢驗項目有血清學檢查，包括B型肝炎表面抗原、表面抗體、核心抗體(HBsAg、anti-HBs、anti-HBc)、C型肝炎抗體(anti-HCV)和一般生化檢查，另外對於C型肝炎抗體陽性學生檢驗HCV RNA，同時也選取居住在高雄市國小學生當作對照組。此外，針對大武鄉學生持續追蹤二年。 結果： 有1470人(83.5%)參加本次研究，其中原住民學生有1247人，漢族學生有159位，另外有64人因資料及血液收集不全而被排除。原住民地區學生B型肝炎表面抗原、表面抗體和核心抗體陽性盛行率分別是3.5%、45.0%和8.4%，城市地區學生B肝炎表面抗原、表面抗體和核心抗體陽性盛行率分別是0.2%、51.2%和1.7%，兩地區比較有明顯的差異；C型肝炎抗體陽性盛行率在原住民地區是0.4%，在城市地區是0%，兩者無明顯差異；C型肝炎盛行率與年齡層、種族、性別無明顯差異。針對大武地區學生連續兩年的追蹤，發現B型肝炎抗體陽性率有明顯的減少，此外，完整疫苗接種與不完整疫苗接種在B型肝炎血清標記的比較也無差異；研究期間沒有人有新的HBsAg感染。有6位(1.7%)學生雖然接受完整疫苗接種仍然是HBsAg陽性。 結論： 台灣地區實施B型肝炎疫苗接種二十年後，不僅在都市地區，在原住民地區也明顯降低B型肝炎感染情形，而C型肝炎盛行率也因為醫療衛生的改善使得原住民地區盛行率相似於都市地區，而原住民地區成人高C型肝炎盛行率主要原因是出校園後增加暴露於C型肝炎危險因子環境有關；雖然B型肝炎表面抗體陽性率會隨著年紀增加而逐漸減少，對於抗體陰性在嬰兒時期已經接受完整疫苗接種的人，並不需要補追加疫苗；而母親傳染給嬰兒的途徑在造成接種疫苗失敗過程中扮演很重要的角色，如何減少疫苗接種失敗將是未來努力的目標。
並列摘要
Background and purpose: Taiwan is an endemic area of hepatitis. According to reports, the carrier rate of hepatitis B surface antigen (HBsAg) and antibody to hepatitis C virus (anti-HCV) in healthy adults has been as much as 15-20% and 1-2%, respectively. The prevalence rate of hepatitis among adults in aboriginal areas is higher than in urban areas. The frequency of hepatitis B infection has declined greatly after a nationwide vaccination program was launched in 1984. It is more important to clarify whether the prevalence of hepatitis B and C is also higher among schoolchildren, and further evaluate the vaccine effect in aboriginal areas. Material and Method: A total of 1755 schoolchildren from 13 elementary schools and 4 junior high schools in four aboriginal country townships: Taoyuan, Sanmin, Maolin, and Dawu, were invited to participate in the study from November 2004 to October 2006. A structured questionnaire and serologic test were completed. Blood samples were tested for HBsAg, anti-HBs, anti-HBc, anti-HCV and biochemistry. Besides, HCV RNA was determined for those seropositive for anti-HCV. Meanwhile, we randomly selected Han Chinese students who lived in the urban area of Kaohsiung City as a control. Besides, a two-year follow-up among students in Dawu Township was performed. Results: A total of 1470 (83.5%) students participated in this study, including 1247 aboriginal students and 159 Han Chinese students. 64 students who failed to provide blood samples were excluded. The seropositive prevalence of HBsAg, anti-HBs , anti-HBc among students in aboriginal areas were 3.5%, 45.0% and 8.4% respectively, which was quite different to the prevalence of 0.2%, 51.2% and 1.7% in the urban area. The prevalence of anti-HCV-positive was 0.4% in aboriginal areas and 0% in urban area. There was neither an ethnic nor geographic difference in the distribution of anti-HCV seropositivity. After a two-year follow-up in Dawu Township, the positive rate of anti-HBs had significantly declined . Besides, there was no difference between vaccinated and unvaccinated students. No one had new HBsAg-positive during the period of study. There were 6 HBsAg-positive students although they had received complete vaccination. Conclusion: Not only urban areas, but also aboriginal areas have reduced hepatitis B infection rates after twenty years of a universal hepatitis B vaccination program in Taiwan. The prevalence of anti-HCV among students in aboriginal areas was similar to urban areas because of improvement of medical services and hygiene. The higher prevalence of anti-HCV among aboriginal adults might be due to increased exposure to risk factors after the school-age period. Although the rate of anti-HBs seropositivity gradually decreased with increasing age, there was no necessity for a booster vaccination for those individuals with negative-anti-HBs after a previous complete vaccination in infancy. Mother-to-infant transmission plays an important role in vaccine failure. Studying how to decrease vaccine failure is an aim for the future.