Europe, the United States, China in modern history. . . Repeated outbreaks of pandemic influenza (such as h1n1) have extremely high mortality rates, which are closely related to war and poverty.
1) The infection is fast.
2) Easy to popularize.
3) The new generation is immune.
4) The old generation lacked immunity.
5) Elderly people are deadly.
6) Similar to flu.
7) Complications are mainly pneumonia.
8) The case fatality rate is not high.
9) Protection is needed, but the severity of the epidemic has been hyped up by high-tech professionals to hijack the population and threaten the country.