慢性肝病與肝癌為台灣第十大死因，與慢性病毒性肝病密切相關。本研究旨在探討B型肝炎疫苗接種世代青少年抗體效力狀況。B肝疫苗抗體效力之免疫記憶性因個體而有差異。此為追朔性研究，以1996/09至2002/08出生1,803位青少年B肝抗原與抗體數據，探討抗體保護力及免疫長期記憶性變化。1,803位青少年中，24位HBsAg陽性帶原者；排除後進行Anti-HBs效價統計，結果發現380位1997/09至1998/08出生的世代於2015/05篩檢時，13.95%保護力不足；316位2001/09至2002/08出生的世代於2019/05篩檢時，保護效力不足比例升高至54.11%。相較於1997出生世代，2002年出生世代Anti-HBs效力顯著下降(p<.0001)，暗示免疫長期記憶性銳降。當青少年B型肝炎免疫記憶性下降，高度危險群應主動接受抗體檢測或追加疫苗接種，降低B型肝炎病毒感染危險。

Chronic liver disease and liver cancer are the 10th death cause in Taiwan and related to chronic viral liver disease. The aim of this study was to investigate the efficacy of hepatitis B antibody (Anti-HBs) in adolescents of hepatitis B vaccination. The persistence (immune memory) of Anti-HBs efficacy after vaccination varies from individual. In this retrospective study, the HBsAg and Anti-HBs data of 1803 juveniles, who were born from 1996/09 to 2002/08, were analyzed to investigate Anti-HBs protection and immune long-term memory changes. Twenty-four of the 1803 adolescents were HBsAg(+) carrier. After HBsAg(+) excluded, the titer of Anti-HBs were statistics analyses. We found that in 2015/05, 13.95% of the 380 adolescents, who were born between 1997/09 and 1998/08, had insufficient Anti-HBs protection. In 2019/05, 54.11% of the 316 adolescents, who were born between 2001/09 and 2002/08, had insufficient Anti-HBs protection. Compared with the 1997 birth generation, the efficacy of Anti-HBs protection was significantly decreased with the 2002 birth generation (P<.0001), suggesting a significant decrease in long-term memory of immunization. When the immune memory of Anti-HBs declines in teenager, the high-risk group of hepatitis B should take the initiative to receive Anti-HBs titer test or additional vaccinate to reduce the risk of hepatitis B virus infection.