实验用冷适应重组株按苏联常规方法制备,甲_1型疫苗株为47/25/1重组株,甲_3型疫苗株为47/7/2重组株。单价疫苗每ml 10~(7.5)EID_(50),使用前1:2稀释。双价疫苗由两种未稀释的单价疫苗于使用前混合而成。安慰剂系未曾感染的正常鸡胚尿囊液,使用前1:2稀释。人群接种为鼻腔喷雾,每侧鼻腔内接种0.25ml疫苗(10~(7.0)EID_(50)),21天后以同法实行再接种。选择健康儿童分成两组:1组接受疫苗;另1组接受安慰剂。第1次接种后观察5天,并测量体温,以评价局部和全身反应。于接种前、第1次接种后21天及第2次接种后21天采集双份如清,以Alexandrova改良法测定血凝素(HA)抗体滴度,以洗脱-抑制试 The experimental cold-adapted recombinant strain was prepared according to the conventional method of the Soviet Union. The vaccine strain A_1 was 47/25/1 and the vaccine strain A_3 was 47/7/2. Monovalent vaccine 10 ~ (7.5) EID_ (50) per ml, diluted 1: 2 before use. The bivalent vaccine is made by mixing two undiluted monovalent vaccines before use. Placebo was normal chicken embryo allantoic fluid that had never been infected, diluted 1: 2 before use. The population was inoculated with a nasal spray and inoculated with 0.25 ml of vaccine (10-7.0 EID 50) on each side of the nasal cavity. After 21 days, the vaccine was re-vaccinated. Healthy children were divided into two groups: one received vaccine; the other received placebo. Five days after the first vaccination, body temperature was measured to evaluate local and systemic reactions. Pre-inoculation, 21 days after the first inoculation and 21 days after the second inoculation, duplicate samples were collected, and the titer of the HA antibody was measured by the Alexandrova modified method. The elution-inhibition test