美国每年都有流感病毒感染发生,但在发病率和地理分布上变化很大。流感病毒感染可以无症状,亦可产生从轻度上呼吸道感染到肺炎乃至死亡等各种表现。甲型和乙型流感病毒仅仅是造成整个呼吸道疾病的部分原因。但在成人和儿童中,他们是唯一能够引起周期性广泛传播的发热性呼吸道疾病。流感的流行,常常引起死亡率增高。在1968～1980年间,美国在流感流行期间估计多死亡了150,000人以上。美国预防或控制流感的努力,目的在于 Influenza virus infection occurs every year in the United States, but the incidence and geographical distribution vary greatly. Influenza virus infection can be asymptomatic, can also produce from mild upper respiratory tract infection to pneumonia and even death and other performance. Influenza A and B viruses are only part of the cause of the entire respiratory disease. But among adults and children, they are the only febrile respiratory diseases that can cause widespread cyclicality. The prevalence of the flu often leads to increased mortality. Between 1968 and 1980, the United States is estimated to have killed more than 150,000 more during the flu epidemic. The U.S. efforts to prevent or control the flu are aimed at