运用双盲法对医院中有高度感染危险的医务人员进行乙型肝炎（HBV）免疫性预防效果分析。1968—1972年期间，尽管该院采取了一系列措施，但仍有5—8％的发病率，每年平均为12—19例病人发生。 Double-blind method was used to analyze the preventive effect of Hepatitis B (HBV) immunity on medical staff in hospitals who were at high risk of infection. Between 1968 and 1972, despite a series of measures taken by the hospital, there were still 5-8% morbidity rates, averaging 12-19 cases per year.