The World Health Organization (WHO ) declared the coronavirus crisis a “pandemic ” on March 11 of 2020 .
世界卫生组织（世卫组织）于2020年3月11日宣布新冠病毒危机为“大流行”。
He was reminding people that the word is used only for the most extreme and dangerous spreads of disease .
他提醒人们，这个词只用于描述最极端、最危险的疾病传播。
The number of deaths from the disease is about 4.7 million .
死于这种疾病的人数约为470万。
At the same time , new versions , or variants , of the SARS-CoV-2 virus that causes COVID-19 are developing and spreading very fast .
与此同时，引发新冠肺炎的SARS-CoV-2病毒的新版本（即变异株）正在出现并迅速传播。
In the United States , the Centers for Disease Control and Prevention (CDC ) said the Delta variant is the main cause of new COVID infections .
在美国，疾病控制与预防中心（CDC）表示，德尔塔变异株是新增新冠感染的主要原因。
Governments and health officials around the world reacted to the crisis by establishing the largest vaccination program in history .
世界各国政府和卫生官员通过推出史上规模最大的疫苗接种计划来应对危机。
Data collected by the Bloomberg company shows that by September , more than 5.9 billion shots of vaccine have been administered to people across 184 countries .
彭博公司收集的数据显示，截至9月，184个国家已接种超过59亿剂疫苗。
Michael Osterholm is an expert on epidemics at the University of Minnesota in Minneapolis .
迈克尔·奥斯特霍尔姆是明尼阿波利斯明尼苏达大学的流行病专家。
He told Nature that ending the existence of the virus right now is unrealistic .
他对《自然》杂志说，现在就消灭这种病毒是不现实的。
He compared it to trying to build “a stepping-stone pathway to the Moon .”
他把这比作试图修建“一条通往月球的垫脚石小路”。
The World Health Organization defines pandemics , epidemics , and endemics based on a disease's rate of spread .
世界卫生组织根据疾病的传播速度来定义大流行、流行病和地方病。
For example , the Ebola outbreak that spread within West African countries from 2014-2016 was called an epidemic .
例如，2014年至2016年在西非国家蔓延的埃博拉疫情被称为流行病。
In 2016 , the world's health agency declared that the Zika virus was a “Public Health Emergency of International Concern .”
2016年，世界卫生机构宣布寨卡病毒为“国际关注的突发公共卫生事件”。
The insects called mosquitos pass the disease to humans when they bite them .
被称为蚊子的昆虫在叮咬人类时会传播这种疾病。
Zika was first discovered in Africa and Asia before spreading to Brazil and other South American countries .
寨卡病毒最早在非洲和亚洲被发现，之后传播到巴西和其他南美国家。
Some considered Zika an epidemic while others view it as a pandemic like the current coronavirus health crisis .
有些人认为寨卡是流行病，另一些人则把它视为与当前新冠危机一样的大流行。
The difference between an epidemic and a pandemic is not in the severity of the disease , but the degree to which it has spread .
流行病和大流行的区别不在于疾病的严重程度，而在于其传播范围。
A pandemic means a disease has spread to several countries around the world .
大流行是指一种疾病已传播到世界多个国家。
Epidemic is used to mean disease spreads in smaller areas .
流行病指的是疾病在较小范围内传播。
The word endemic came from the Greek word endēmos , meaning “in the population .”
endemic（地方病）一词源自希腊语endēmos，意思是“在人群之中”。
In public health , it is used to describe a disease outbreak that is present and limited to an area .
在公共卫生领域，它用来描述存在于并局限于某一地区的疾病暴发。
This makes the disease spread and rates easier to control .
这使得疾病的传播和发病率更容易控制。
Malaria , for example , is considered an endemic in many warm , wet areas across countries in Asia , Africa , and South America .
例如，疟疾在亚洲、非洲和南美洲国家的许多温暖潮湿地区被视为地方病。
The H1N1 influenza virus is also endemic .
H1N1流感病毒也属于地方病。
Christopher Dye studies epidemics at Britain's University of Oxford .
克里斯托弗·戴伊在英国牛津大学研究流行病。
They wrote about the disease in the online news site The Conversation .
他们在在线新闻网站The Conversation上撰文讨论了这种疾病。
The scientists said that with face coverings and vaccination , the COVID-19 pandemic “could disappear like smallpox or polio did ….”
科学家们表示，有了口罩和疫苗接种，新冠大流行“可能会像天花或小儿麻痹症那样消失……”
But they said the disease could also become endemic over time .
但他们说，随着时间推移，这种疾病也可能成为地方病。
They said viruses are more likely to become endemic if they are adapted to “a local environment ” of people with “low or zero immunity .”
他们说，如果病毒适应了“免疫力低或没有免疫力”人群的“当地环境”，就更有可能成为地方病。
And vaccination rates will affect the progress of the disease .
而疫苗接种率将影响疾病的发展。
A low vaccine rate could permit the virus to continue at an epidemic level for longer , they wrote .
他们写道，疫苗接种率低可能会让病毒在更长时间内保持流行病水平。