There was so much to look forward to at the start of 2021 .
2021年初，有太多值得期待的事情。
The question was when , and not if , the health crisis that spread from a market in Wuhan , China would finally end .
问题不在于这场从中国武汉一个市场蔓延开来的卫生危机是否会结束，而在于何时结束。
Scientists developed two highly effective vaccines against the coronavirus in record time .
科学家们以创纪录的速度研发出两种针对冠状病毒的高效疫苗。
Several more were waiting for approval .
还有几种疫苗正在等待批准。
Governments in the United States , Europe , and Israel spent billions of dollars to start the biggest vaccination program in history .
美国、欧洲和以色列政府斥资数十亿美元，启动了史上规模最大的疫苗接种计划。
China and Russia developed their own vaccines .
中国和俄罗斯研发了自己的疫苗。
And the UN-backed COVAX program purchased shots for developing and poor countries around the world .
此外，联合国支持的“新冠疫苗实施计划”（COVAX）为世界各地的发展中国家和贫穷国家购买了疫苗。
In May , the U.S . and Western nations expanded the program to vaccinate young children .
5月，美国和西方国家扩大了疫苗接种计划，开始为幼童接种。
Health officials issued new guidelines advising that fully vaccinated people no longer needed to wear face coverings in most situations .
卫生官员发布了新指南，称完全接种疫苗的人在大多数情况下不再需要戴口罩。
The move was seen as the first step toward returning to normal conditions that existed before the pandemic .
此举被视为恢复疫情前正常状态的第一步。
But , scientists began to worry about the new versions of the coronavirus , called variants , soon after people started to receive the new vaccines .
但人们开始接种新疫苗后不久，科学家们就开始担心冠状病毒的新版本，也就是变异株。
It is normal for viruses to mutate , or change , over time .
病毒随着时间推移发生突变或变化是很正常的。
A mutation that strengthens the virus helps it to spread by pushing out the weaker versions .
让病毒变强的突变会把较弱的版本挤掉，从而帮助病毒传播。
In February , the head of Britain's vaccination effort said the world faced around 4,000 variants of the virus that causes COVID-19 .
今年2月，英国疫苗接种工作负责人说，全世界面临着大约4000种新冠病毒变异株。
But only some would raise concern .
但只有一部分会引起担忧。
The two most worrisome variants now are Delta and Omicron .
目前最令人担忧的两种变异株是德尔塔和奥密克戎。
In the early days of the pandemic , many Asian countries appeared to have successfully fought the virus with strong measures .
疫情初期，许多亚洲国家似乎通过强有力的措施成功抗击了病毒。
By July , countries , including Japan , South Korea , Vietnam , and Thailand , were setting records for new cases and deaths .
到7月，日本、韩国、越南和泰国等国的新增病例和死亡人数都在创下纪录。
The Delta variant appeared at a difficult time .
德尔塔变异株出现在一个困难时期。
When it started being reported , vaccination rates remained low in many countries .
当它开始被报告时，许多国家的疫苗接种率仍然很低。
And officials were moving quickly to reopen economies .
而且官员们正迅速推动重新开放经济。
Then , infections of the Delta variant became widespread .
随后，德尔塔变异株的感染大面积蔓延。
Governments , businesses , and schools reacted with more vaccination requirements and restrictions .
政府、企业和学校纷纷出台更多的疫苗接种要求和限制措施来应对。
Some countries started to restrict international travelers and closed borders over concerns about the fast-spreading Omicron variant .
一些国家因担心快速传播的奥密克戎变异株，开始限制国际旅客入境并关闭边境。
After another year of face coverings , restrictions , vaccines and variants , people are beginning to wonder whether this pandemic will ever go away .
又经历了一年的口罩、限制措施、疫苗和变异株，人们开始怀疑这场大流行是否会有结束的一天。
The answer is yes and no .
答案是既会也不会。
Many scientists believe that the new coronavirus is here to stay .
许多科学家认为，新型冠状病毒将长期存在。
In February , the science publication Nature reported the results of a study involving more than 100 scientists .
今年2月，科学期刊《自然》报道了一项有100多名科学家参与的研究结果。
Endemic means the virus will continue to exist in some areas for years to come .
地方性流行意味着病毒将在未来多年里继续在某些地区存在。
For example , Malaria is considered endemic to many warm , wet areas across countries in Asia , Africa , and South America .
例如，疟疾被认为是亚洲、非洲和南美洲许多国家湿热地区的地方病。
But it is not a problem in the United States or other Western nations .
但在美国或其他西方国家，它并不是问题。
The way to end a pandemic is to reach herd immunity .
结束大流行的方法是实现群体免疫。
Herd immunity is when many people in a community either have recovered from an infection or have been vaccinated .
群体免疫是指一个社区中的许多人要么已从感染中康复，要么已接种疫苗。
It does not mean everyone is protected from the virus .
这并不意味着每个人都能免受病毒侵害。
However , when herd immunity is reached , the virus can no longer spread easily , which helps protect those who are at risk .
然而，一旦实现群体免疫，病毒就无法再轻易传播，这有助于保护高风险人群。
As nations joined together to fight the pandemic , health officials started to sound the alarm about another public health crisis : mental health .
在各国联手抗击疫情之际，卫生官员开始对另一场公共卫生危机——心理健康——发出警告。
There is hope , however .
不过，希望仍在。
Although health officials have already approved several treatments for COVID-19 , all of them must be injected by healthcare workers .
尽管卫生官员已经批准了几种新冠治疗药物，但都必须由医护人员注射。
But pills can be taken at home and are easier to send around the world .
但药丸可以在家服用，而且更容易运往世界各地。
And I'm Mario Ritter , Jr .
我是小马里奥·里特。