The World Health Organization (WHO ) declared the coronavirus crisis a “pandemic ” on March 11 of 2020 .
世界衛生組織（世衛組織）於2020年3月11日宣布新冠病毒危機為「大流行」。
He was reminding people that the word is used only for the most extreme and dangerous spreads of disease .
他提醒人們，這個詞只用於描述最極端、最危險的疾病傳播。
The number of deaths from the disease is about 4.7 million .
死於這種疾病的人數約為470萬。
At the same time , new versions , or variants , of the SARS-CoV-2 virus that causes COVID-19 are developing and spreading very fast .
與此同時，引發新冠肺炎的SARS-CoV-2病毒的新版本（即變異株）正在出現並迅速傳播。
In the United States , the Centers for Disease Control and Prevention (CDC ) said the Delta variant is the main cause of new COVID infections .
在美國，疾病管制與預防中心（CDC）表示，Delta變異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 .
世界各國政府和衛生官員透過推出史上規模最大的疫苗接種計畫來應對危機。
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 .
彭博公司收集的數據顯示，截至9月，184個國家已接種超過59億劑疫苗。
Michael Osterholm is an expert on epidemics at the University of Minnesota in Minneapolis .
麥可·奧斯特霍姆是明尼亞波利斯明尼蘇達大學的流行病專家。
He told Nature that ending the existence of the virus right now is unrealistic .
他對《自然》期刊說，現在就消滅這種病毒是不切實際的。
He compared it to trying to build “a stepping-stone pathway to the Moon .”
他把這比作試圖修建「一條通往月球的墊腳石小路」。
The World Health Organization defines pandemics , epidemics , and endemics based on a disease's rate of spread .
世界衛生組織根據疾病的傳播速度來定義大流行、流行病和地方性流行病。
For example , the Ebola outbreak that spread within West African countries from 2014-2016 was called an epidemic .
例如，2014年至2016年在西非國家蔓延的伊波拉疫情被稱為流行病。
In 2016 , the world's health agency declared that the Zika virus was a “Public Health Emergency of International Concern .”
2016年，世界衛生機構宣布茲卡病毒為「國際關注公共衛生緊急事件」。
The insects called mosquitos pass the disease to humans when they bite them .
被稱為蚊子的昆蟲在叮咬人類時會傳播這種疾病。
Zika was first discovered in Africa and Asia before spreading to Brazil and other South American countries .
茲卡病毒最早在非洲和亞洲被發現，之後傳播到巴西和其他南美國家。
Some considered Zika an epidemic while others view it as a pandemic like the current coronavirus health crisis .
有些人認為茲卡是流行病，另一些人則把它視為與當前新冠危機一樣的大流行。
The difference between an epidemic and a pandemic is not in the severity of the disease , but the degree to which it has spread .
流行病和大流行的區別不在於疾病的嚴重程度，而在於其傳播範圍。
A pandemic means a disease has spread to several countries around the world .
大流行是指一種疾病已傳播到世界多個國家。
Epidemic is used to mean disease spreads in smaller areas .
流行病指的是疾病在較小範圍內傳播。
The word endemic came from the Greek word endēmos , meaning “in the population .”
endemic（地方性流行病）一詞源自希臘語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 .
在公共衛生領域，它用來描述存在於並侷限於某一地區的疾病爆發。
This makes the disease spread and rates easier to control .
這使得疾病的傳播和發病率更容易控制。
Malaria , for example , is considered an endemic in many warm , wet areas across countries in Asia , Africa , and South America .
例如，瘧疾在亞洲、非洲和南美洲國家的許多溫暖潮濕地區被視為地方性流行病。
The H1N1 influenza virus is also endemic .
H1N1流感病毒也屬於地方性流行病。
Christopher Dye studies epidemics at Britain's University of Oxford .
克里斯多福·戴伊在英國牛津大學研究流行病。
They wrote about the disease in the online news site The Conversation .
他們在線上新聞網站The Conversation上撰文討論了這種疾病。
The scientists said that with face coverings and vaccination , the COVID-19 pandemic “could disappear like smallpox or polio did ….”
科學家們表示，有了口罩和疫苗接種，新冠大流行「可能會像天花或小兒麻痺症那樣消失……」
But they said the disease could also become endemic over time .
但他們說，隨著時間推移，這種疾病也可能成為地方性流行病。
They said viruses are more likely to become endemic if they are adapted to “a local environment ” of people with “low or zero immunity .”
他們說，如果病毒適應了「免疫力低或沒有免疫力」人群的「當地環境」，就更有可能成為地方性流行病。
And vaccination rates will affect the progress of the disease .
而疫苗接種率將影響疾病的發展。
A low vaccine rate could permit the virus to continue at an epidemic level for longer , they wrote .
他們寫道，疫苗接種率低可能會讓病毒在更長時間內維持流行病水準。