流行性感冒简称流感,是由流感病毒引起的急性呼吸道传染病,常导致严重的并发症,从而造成许多患者尤其是老年病人的死亡,是一种严重危害人类健康致死率最高的急性病毒性传染病之一。对于流感目前尚无特别有效的治疗方法,接种疫苗是目前所知预防和控制流感的唯一手段。并且由于流感病毒的抗原变异,流感疫苗的免疫只对一年有效,需每年接种一次。近几年流感病毒一直处于大流行前的变异活跃期,发生流 The flu, which is referred to as flu, is an acute respiratory infection caused by the influenza virus. It often leads to serious complications that result in the death of many patients, especially the elderly. It is an acute viral infection that seriously endangers the death toll of human health One of the diseases. Vaccination is currently the only means known to prevent and control influenza, with no particularly effective treatment for influenza. And because of the antigenic variation of the influenza virus, the immunity to the flu vaccine is only valid for one year and needs to be inoculated once a year. In recent years, the influenza virus has been in an active phase of mutation before the pandemic and a flow occurs