流行性感冒和急性呼吸道卡他尔的预防,应当在医疗预防机关以及卫生防疫机关中占据一个显著的地位。这个问题的重要性,每个医务工作者都是很清楚的;因为流行性感冒和急性呼吸道卡他尔,是最普遍的传染病。但是不久以前我们对於这种疾病的知识,还是非常有限的,而防治它的方法,效果也很小。现在已经确定病毒性流感有三种病原体:A,A_1及B型病毒。流感的三种病原体,引起的疾病的临床经过虽然十分类似,但是某些生物学和免疫学方面的特性,是彼此不相同的。三种流感病原体的抗原结构的差异,乃成为缺乏交叉免疫的 Prevention of influenza and acute respiratory catarrhal should occupy a prominent place in the medical prevention agencies as well as the health and epidemic prevention agencies. The importance of this issue is clear to every health worker; because of the flu and the acute respiratory catarrhal, it is the most common infectious disease. But not long ago our knowledge of the disease was still very limited, and the methods of preventing and curing it were not very effective. It has now been established that there are three types of viral pathogens: A, A_1 and B viruses. Although the clinical course of the three pathogens causing the disease is very similar, some of the biological and immunological characteristics are different from each other. The differences in the antigenic structures of the three influenza pathogens are lack of cross-immunization