As the COVID-19 （Corona Virus Disease 2019） continues to spread around the world， the words epidemic and pandemic are showing up in news reports more often than they usually do. While the terms are closely related， they dont refer to the same thing.

新冠肺炎持续在全球传播之际，epidemic和pandemic这两个词比往常更频繁地在新闻报道中出现。尽管这两个词意思很相近，但二者所指并不相同。

As the Association for Professionals in Infection Control and Epidemiology （APIC） explains on its website， “an epidemic occurs when an infectious disease spreads rapidly to many people.” Usually， what precedes an epidemic is an outbreak， or “a sudden rise in the number of cases of a disease.” An outbreak can affect a single community or several countries， but its on a much smaller scale than an epidemic.

正如感染控制和流行病学专业人士协会在网站上解释道：“当一种传染性疾病迅速传播给许多人时，就被称为流行病（epidemic）。”通常，epidemic发生之前会有疾病暴发（outbreak），即“某种疾病案例的突然增加”。outbreak可能影响到单个社区或几个国家，但规模比epidemic小得多。

If an epidemic cant be contained and keeps expanding its reach， public health officials might start calling it a pandemic， which means its affected enough people in different areas of the world to be considered a global outbreak. In short， a pandemic is a worldwide epidemic. It infects more people， causes more deaths， and can also have widespread social and economic repercussions. The spread of the Spanish influenza from 1918 to 1919， which killed between 20 and 40 million people around the world， was a pandemic; more recently， the H1N1 influenza created a pandemic in 2009.

如果一场epidemic不能被控制住，还在不断蔓延，公共卫生官员可能就要开始称之为大流行病（pandemic），意思是这场流行病已经影响到世界不同地区足够多的人，到了全球性暴发的程度。简而言之，pandemic就是全球性epidemic。pandemic感染的人更多，导致的死亡人数更多，还可能对社会和经济造成广泛的影响。1918—1919年间的西班牙流感在全世界导致2000万至4000万人丧生，这种流行病属于pandemic;離现在更近的2009年的甲型流感也是pandemic。

Heres where it gets a little tricky： Theres no cut-and-dried classification system for outbreaks， epidemics， and pandemics.

这里有个微妙之处：outbreak，epidemic和pandemic三者之间并没有既成的区分体系。

Vocabulary

COVID-19  新型冠状病毒肺炎，简称“新冠肺炎”

epidemic  n. 流行病

pandemic  n. （全国或全球性）流行病;大流行病

outbreak  n. （暴力、疾病等坏事的）爆发，突然发生

repercussion  n. （间接的）影响，反响，恶果