VOA健康报道2022--专家称奥密克戎之后可能会有更多变种

Experts: More Variants² after Omicron Likely

Scientists warn that the fast-spreading Omicron will likely not be the last worrisome version of the coronavirus.

The Omicron version of the coronavirus was first identified in mid-November. By the first week of January, the World Health Organization reported a record 15 million new COVID-19 cases. That is a 55 percent increase from the previous week.

Every new infection provides a chance for the virus to mutate, or change. The fast spread of Omicron means the virus has more chances to develop new versions, called variants.

Scientists do not know what the next variants will look like or how they might shape the pandemic. But they say there is no guarantee that new coronavirus variants will cause milder illness or that existing vaccines³ will work against them. And they urge wider vaccination⁴ now, while the shots still work against the virus.

Dr. Leonardo Martinez is an infectious disease expert at Boston University. He said, "The faster Omicron spreads, the more opportunities there are for mutation⁵, potentially leading to more variants."

More contagious⁶, breakthrough infections

Research shows that Omicron is at least two times as contagious as the Delta⁷ variant¹ and four times more contagious than the original version of the virus. Contagious means the variant could easily pass between people.

Omicron is also more likely than Delta to reinfect individuals who previously⁸ had COVID-19 and to cause "breakthrough infections" - meaning to cause an infection even if a person is vaccinated⁹.

The variant's quick spread increases the chances that the virus will infect and remain inside people with weakened immune systems - giving it more time to develop mutations or changes.

Dr. Stuart Campbell Ray of Johns Hopkins University said, "It's the longer...infections that seem to be the most likely breeding grounds for new variants." He added more infections also increased the chances for that to happen.

Other possibilities for the virus

Since Omicron appears to cause less severe disease than Delta, there is hope that it could make the virus milder like a common cold. It is a possibility, experts say, given that viruses do not spread well if they kill their hosts very quickly. But viruses do not always get less deadly over time.

Ray explained that a variant could realize its main goal – replicating¹⁰ or reproducing – if it caused mild infections at first then caused severe illness later. This would give time for an infected person to spread the virus to others before getting very sick.

Ray added, "I don't think we can be confident that the virus will become less lethal¹¹ over time." Lethal is a term that means deadly.

When SARS-CoV-2, the virus that caused COVID-19, first appeared, no one was immune. But infections and vaccines have given at least some immunity¹² to much of the world, so the virus must change to survive and spread to others.

There are many possible ways for such change to take place.

Animals could possibly release new variants. Dogs and cats, deer and farm-raised mink¹³ are some of the animals that could be infected by the virus. The virus could mutate within them and then jump back to people.

Another possibility is that people could get infected with both Omicron and Delta at the same time. Such infections could create what Ray calls "Frankenvariants" with qualities of both variants.

When new variants do develop, scientists said it is still very difficult to know which ones might spread. For example, Omicron has 30 mutations that let it attach easily to human cells. But the IHU variant, identified in France, has 46 mutations and does not seem to have spread much at all.

To control or limit the spread of new variants, scientists stress continuing with public health measures such as wearing face coverings and getting vaccinated.

Louis Mansky is director of the Institute for Molecular¹⁴ Virology at the University of Minnesota. He said with so many unvaccinated people, "the virus is still kind of in control of what's going on."

Words in This Story

opportunity – n. an amount of time or a situation in which something can be done

mutation – n. biology : a change in the genes¹⁵ of a plant or animal that causes characteristics that are different from what is normal; a new form of something that has changed

contagious – adj. able to be passed from one person or animal to another by touching¹⁶

immune system– n. the system that protects your body from diseases and infections

1 variant   

adj.不同的，变异的；n.变体，异体

参考例句：

• We give professional suggestions according to variant tanning stages for each customer.我们针对每位顾客不同的日晒阶段，提供强度适合的晒黑建议。
• In a variant of this approach,the tests are data- driven.这个方法的一个变种，是数据驱动的测试。

2 variants   

n.变体( variant的名词复数 )；变种；变型；（词等的）变体

参考例句：

• Those variants will be preserved in the'struggle for existence". 这些变异将在“生存竞争”中被保留下来。 来自辞典例句
• Like organisms, viruses have variants, generally called strains. 与其他生物一样，病毒也有变种，一般称之为株系。 来自辞典例句

3 vaccines   

疫苗，痘苗( vaccine的名词复数 )

参考例句：

• His team are at the forefront of scientific research into vaccines. 他的小组处于疫苗科研的最前沿。
• The vaccines were kept cool in refrigerators. 疫苗放在冰箱中冷藏。

4 vaccination   

n.接种疫苗，种痘

参考例句：

• Vaccination is a preventive against smallpox.种痘是预防天花的方法。
• Doctors suggest getting a tetanus vaccination every ten years.医生建议每十年注射一次破伤风疫苗。

5 mutation   

n.变化，变异，转变

参考例句：

• People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
• So far the discussion has centered entirely around mutation in the strict sense.到目前为止，严格来讲，讨论完全集中于围绕突变问题上。

6 contagious   

adj.传染性的，有感染力的

参考例句：

• It's a highly contagious infection.这种病极易传染。
• He's got a contagious laugh.他的笑富有感染力。

7 delta   

n.（流的）角洲

参考例句：

• He has been to the delta of the Nile.他曾去过尼罗河三角洲。
• The Nile divides at its mouth and forms a delta.尼罗河在河口分岔，形成了一个三角洲。

8 previously   

adv.以前，先前（地）

参考例句：

• The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
• Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。

9 vaccinated   

[医]已接种的，种痘的，接种过疫菌的

参考例句：

• I was vaccinated against tetanus. 我接种了破伤风疫苗。
• Were you vaccinated against smallpox as a child? 你小时候打过天花疫苗吗？

10 replicating   

复制( replicate的现在分词 )； 重复； 再造； 再生

参考例句：

• Applications create these partitions for storing and replicating data. 应用程序创建这些分区用来储存和复制数据。
• The closest real things to these creatures were bits of self-replicating RNA. 最贴近这些造物的实物是能做一点微不足道的自复制的核糖核酸。

11 lethal   

adj.致死的；毁灭性的

参考例句：

• A hammer can be a lethal weapon.铁锤可以是致命的武器。
• She took a lethal amount of poison and died.她服了致命剂量的毒药死了。

12 immunity   

n.优惠；免除；豁免，豁免权

参考例句：

• The law gives public schools immunity from taxation.法律免除公立学校的纳税义务。
• He claims diplomatic immunity to avoid being arrested.他要求外交豁免以便避免被捕。

13 mink   

n.貂，貂皮

参考例句：

• She was wearing a blue dress and a mink coat.她穿着一身蓝色的套装和一件貂皮大衣。
• He started a mink ranch and made a fortune in five years. 他开了个水貂养殖场，五年之内就赚了不少钱。

14 molecular   

adj.分子的；克分子的

参考例句：

• The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
• For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时，分子的碰撞就停止了。

15 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

16 touching   

adj.动人的，使人感伤的

参考例句：

• It was a touching sight.这是一幅动人的景象。
• His letter was touching.他的信很感人。