美国国家公共电台 NPR--Omicron poses about half the risk of long COVID as delta, new research finds

Omicron poses about half the risk of long COVID as delta¹, new research finds

Transcript²

The omicron variant³ is much less likely than delta to cause long COVID, according to the first large-scale study published about the long-term risks posed by omicron.

But almost 5% of people who catch omicron still experience fatigue⁴, brain fog, headaches, heart problems or other health issues at least a month after getting infected, the study found.

While some researchers found the results reassuring⁵, others say the findings are alarming, given that so many people caught omicron and apparently⁶ remain at risk even if they're vaccinated⁷.

"That's scary," says Dr. Akiko Iwasaki, an immunobiologist at Yale School of Medicine who studies long COVID but was not involved in the new research.

"People assume that because omicron is milder that, you know, 'Let's just get infected and get it over with,''' Iwasaki says.

The findings, published Thursday in The Lancet, come from researchers at King's College London who have been tracking thousands of people who test positive for the coronavirus to determine the risk of long COVID from different variants⁸.

"The basic question that we're trying to answer is: 'Is long COVID as common ... in the delta period [as it is] in the omicron period?'" says Dr. Claire Steves, who helped conduct the research. "'What's the risk of going on to get long COVID, given the different variants?'"

The researchers compared 56,003 people who caught omicron from Dec. 20, 2021, through March 9, 2022, with 41,361 people who had caught delta between June 1, 2021, and Nov. 27, 2021, and kept track of their symptoms using a special app.

Those who caught omicron were about half as likely as those who got delta to still be experiencing health problems a month later, the researchers found.

"Thankfully, with the omicron variant, the risk of going on to get long COVID is substantially reduced compared to the delta variant," Steves told NPR in an interview. "That's great news, isn't it?"

It's especially good news because omicron is so contagious⁹ that it has infected an enormous number of people incredibly quickly. If the risk had been the same as delta or higher, the number of people ending up with long COVID would have exploded.

The findings are consistent with a smaller analysis released recently by the British government.

But lower risk does not mean people shouldn't worry about long COVID because of omicron, Steves and others agree. The chance of getting long COVID from omicron is 4.4%, compared with almost 10.8% from delta, according to the study.

"The caveat¹⁰ is that the omicron variant has spread very rapidly through our populations, and therefore a very much larger number of people have been affected¹¹. So the overall absolute number of people who are set to go on to get long COVID, sadly, is set to rise," Steves says. "So it's certainly not a time for us to reduce services for long COVID."

But for any individual person, the findings do indicate that the risk is sharply lower of both getting seriously ill and of developing persistent¹² symptoms.

The study did not address why omicron might pose less of a risk for long COVID. But Steves and others say it makes sense that omicron less frequently leads to persistent symptoms because it doesn't tend to make people as sick as delta.

"Because of that lesser¹³ severity of disease, and also because it seems to be a bit more superficial in terms of the disease ... it's less affecting us in terms of severity of our immune response," Steves says. "And therefore that's leading to less likelihood of long COVID."

Other researchers say these findings need to be confirmed by additional research.

"They just looked at anybody who reported any symptoms over this app. They didn't actually evaluate these patients in a clinic anywhere or collect objective data about them," says Dr. Michael Sneller, who studies long COVID at the National Institutes of Health.

But Sneller says it wouldn't surprise him if omicron is less likely to cause long COVID since it does seem to cause less severe illness.

Some researchers say they hope the findings will correct the misconception that people don't have to worry about long COVID from omicron.

"We're saying, you know: 'You can take off your masks in airplanes. You don't need to be vaccinated anymore to enter a restaurant.' All of these policy decisions are going to increase the likelihood that people get infected with COVID, while there's still a 5% chance of severe chronic¹⁴ illness," says Dr. David Putrino, who treats long COVID at Mount Sinai in New York City. "That's short-sighted and going to create a lot of long-term disability that did not need to exist."

1 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。

2 transcript   

n.抄本，誊本，副本，肄业证书

参考例句：

• A transcript of the tapes was presented as evidence in court.一份录音带的文字本作为证据被呈交法庭。
• They wouldn't let me have a transcript of the interview.他们拒绝给我一份采访的文字整理稿。

3 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。

4 fatigue   

n.疲劳，劳累

参考例句：

• The old lady can't bear the fatigue of a long journey.这位老妇人不能忍受长途旅行的疲劳。
• I have got over my weakness and fatigue.我已从虚弱和疲劳中恢复过来了。

5 reassuring   

a.使人消除恐惧和疑虑的，使人放心的

参考例句：

• He gave her a reassuring pat on the shoulder. 他轻拍了一下她的肩膀让她放心。
• With a reassuring pat on her arm, he left. 他鼓励地拍了拍她的手臂就离开了。

6 apparently   

adv.显然地；表面上，似乎

参考例句：

• An apparently blind alley leads suddenly into an open space.山穷水尽，豁然开朗。
• He was apparently much surprised at the news.他对那个消息显然感到十分惊异。

7 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？

8 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

9 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。

10 caveat   

n.警告； 防止误解的说明

参考例句：

• I would offer a caveat for those who want to join me in the dual calling.为防止发生误解，我想对那些想要步我后尘的人提出警告。
• As I have written before,that's quite a caveat.正如我以前所写，那确实是个警告。

11 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

12 persistent   

adj.坚持不懈的，执意的；持续的

参考例句：

• Albert had a persistent headache that lasted for three days.艾伯特连续头痛了三天。
• She felt embarrassed by his persistent attentions.他不时地向她大献殷勤，使她很难为情。

13 lesser   

adj.次要的，较小的；adv.较小地，较少地

参考例句：

• Kept some of the lesser players out.不让那些次要的球员参加联赛。
• She has also been affected,but to a lesser degree.她也受到波及，但程度较轻。

14 chronic   

adj.(疾病)长期未愈的，慢性的；极坏的

参考例句：

• Famine differs from chronic malnutrition.饥荒不同于慢性营养不良。
• Chronic poisoning may lead to death from inanition.慢性中毒也可能由虚弱导致死亡。