美国国家公共电台 NPR--What science has to say about so-called COVID superdodgers

What science has to say about so-called COVID superdodgers

Transcript²

Throughout the pandemic, some people have avoided catching³ COVID — despite multiple exposures. Do their immune systems have some type of protection that others are missing?

RACHEL MARTIN, HOST:

Maybe you know these people. They're your neighbors or your friends or your family, people out there who seemingly have just dodged⁴ COVID completely. Joining us to talk about this phenomenon is NPR health correspondent Michaeleen Doucleff. Thanks so much for being here.

MICHAELEEN DOUCLEFF, BYLINE⁵: Thank you for having me.

MARTIN: So at this point, it feels like most of us have had at least one bout¹ with COVID. But there is that someone in our lives and you're like, what superpowers do you have that you have not contracted this thing yet?

DOUCLEFF: Exactly. You know, for me, it's this guy named Joe Esparza. I live in Alpine⁶, Texas, now, and he owns the print shop here. And I was talking to him about this, and he told me his entire family has had COVID at different times.

JOE ESPARZA: My first experience with it was when my eldest⁷ son got it.

DOUCLEFF: Then his other son got sick.

ESPARZA: Step and repeat. It all happened again.

DOUCLEFF: Then finally, his wife got it. But during this entire time, Esparza himself never got sick and never even tested positive.

ESPARZA: I have no idea (laughter). But I guess I just got lucky.

MARTIN: What's the explanation?

DOUCLEFF: Well, what scientists are starting to realize is that maybe he got lucky in that he carries a gene⁸ that actually protects him from getting COVID.

MARTIN: OK. So this is a new information. There's a gene that can do that.

DOUCLEFF: Yeah, it's kind of starting to look like that. Esparza may be what some are calling a COVID superdodger. Scientists are just starting to figure out what protects some of them from the disease. But first, there's a really, really interesting history to virus superdodgers that I want to tell you about.

MARTIN: And I want to hear it. Tell me.

DOUCLEFF: OK. So it starts back in the early '90s with this guy, Nathaniel Landau. He was a young HIV researcher at Rockefeller University. He was just starting his career, but he was already on the verge⁹ of making a landmark¹⁰ breakthrough. The breakthrough had to do with what some might call an HIV superdodger. Scientists had just identified groups of people who are completely resistant¹¹ to HIV.

NATHANIEL LANDAU: People who knew they had been multiply exposed to HIV, mainly through unprotected sex, yet clearly they were not infected. So the question was, were these people just lucky or did they really have something that was protecting them from infection?

DOUCLEFF: So scientists all over the world were trying to find the answer.

LANDAU: Yes, we were totally stressed out. There were many labs all racing¹². And we, of course, wanted to be the first.

DOUCLEFF: Landau and his lab were getting really close to answering the question. They had already discovered a huge clue. It had to do with how HIV infects cells. They discovered that the virus needs a little extra help getting inside the cell. It needs to bind¹³ with a very specific molecule¹⁴ on the surface of a human cell in order to enter and infect it. It's a receptor molecule called CCR5.

LANDAU: That was what they call a eureka moment. That was the moment where you could say, I found something that had never been seen before.

DOUCLEFF: Then just a few weeks later, they made the breakthrough they were looking for. They figured out why superdodgers were protected. These people didn't make HIV's helper, CCR5.

LANDAU: We were quite amazed.

DOUCLEFF: Landau and his colleagues found a defect or a mutation¹⁵ in the gene that encodes for CCR5. So these people couldn't make the molecule. And without this molecule, HIV couldn't enter and infect their cells.

LANDAU: The virus sticks to the cell, but it just stays stuck there. It's kind of like it's knocking at the door, but nobody's opening the door. The door is locked.

DOUCLEFF: So no matter how many times a person is exposed to HIV, they couldn't get infected. They're protected and protected for life.

LANDAU: So in the case of resistance to HIV, the story was very clear. You can put as much virus as you want onto those cells, and they will not get infected.

DOUCLEFF: The finding completely shifted the field of HIV. It suggested a way to cure the disease, which scientists are still working on today. But it did something else. It showed scientists that a person could be completely resistant to an infection, a true superdodger. Now, 25 years later, the race is on again with COVID-19. Labs all over the world are racing to understand why people like my friend Joe Esparza may have somehow managed to avoid COVID-19.

JILL HOLLENBACH: It's been challenging and interesting (laughter).

DOUCLEFF: That's Jill Hollenbach. She's an immunogeneticist at the University of California, San Francisco. She's one of the scientists looking for genes¹⁶ that protect people from COVID-19. And after two years of hunting, she and her team have now found something very close. Now, unlike the HIV gene, this mutation doesn't stop an infection, but rather, it increases a person's chances of being completely asymptomatic if they do catch COVID.

HOLLENBACH: Not even a sniffle, not a scratchy throat, entirely¹⁷ asymptomatic.

DOUCLEFF: The gene is called HLA, and this particular mutation on it protects people from getting sick because it helps to clear out the virus very quickly.

HOLLENBACH: That immune response gets just kind of fired up much more quickly so that you basically nuke the infection before you even start to have symptoms.

DOUCLEFF: People with this mutation were armed and ready to fight SARS-CoV-2 even before vaccines¹⁸ came along. They were pre-armed, so to speak.

MARTIN: That is amazing. The people we joke about as having these superpowers, they actually did. They could have this gene that would explain why they never got it.

DOUCLEFF: What's even cooler is that Hollenbach and her team have found that perhaps 10% of people out there have this protective mutation. And for those who tested positive for COVID but were completely asymptomatic, that percentage is likely even higher. So, Rachel, this is not rare.

MARTIN: So interesting. But with this mutation, people still get infected with COVID, right? Have scientists found anything that completely stops COVID from entering a cell like the HIV mutation that you were talking about?

DOUCLEFF: Not yet. No, they haven't. And actually, it might be really hard to find this. Other than HIV, scientists have found only one more example of people who are totally resistant to a viral infection. Specifically, they found people who are completely resistant to a strain of norovirus, which is the vomit¹⁹ bug²⁰.

MARTIN: Oh, yeah, I know it.

DOUCLEFF: Yeah. But really, that's it. Nevertheless, though, several research groups are still searching for a true COVID-resistant gene, and they are actively²¹ looking for COVID superdodgers to participate in their study.

MARTIN: OK. So how do you become someone who qualifies for the experiment?

DOUCLEFF: Yeah. So if you think you've been exposed many times to COVID but never tested positive - and true exposure is like you're living with somebody who's sick - you can send an email to the researchers running the experiment. And if you qualify, the team sends you a little kit²² to collect some of your saliva²³. You mail it back in, and they sequence your entire genome. And we actually have a link to that email that you need online at npr.org.

MARTIN: Such a fascinating story. NPR's Michaeleen Doucleff, thank you so much.

DOUCLEFF: Thank you so much, Rachel.

1 bout   

n.侵袭，发作；一次(阵，回)；拳击等比赛

参考例句：

• I was suffering with a bout of nerves.我感到一阵紧张。
• That bout of pneumonia enfeebled her.那次肺炎的发作使她虚弱了。

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 catching   

adj.易传染的，有魅力的，迷人的，接住

参考例句：

• There are those who think eczema is catching.有人就是认为湿疹会传染。
• Enthusiasm is very catching.热情非常富有感染力。

4 dodged   

v.闪躲( dodge的过去式和过去分词 )；回避

参考例句：

• He dodged cleverly when she threw her sabot at him. 她用木底鞋砸向他时，他机敏地闪开了。 来自《简明英汉词典》
• He dodged the book that I threw at him. 他躲开了我扔向他的书。 来自《简明英汉词典》

5 byline   

n.署名；v.署名

参考例句：

• His byline was absent as well.他的署名也不见了。
• We wish to thank the author of this article which carries no byline.我们要感谢这篇文章的那位没有署名的作者。

6 alpine   

adj.高山的；n.高山植物

参考例句：

• Alpine flowers are abundant there.那里有很多高山地带的花。
• Its main attractions are alpine lakes and waterfalls .它以高山湖泊和瀑布群为主要特色。

7 eldest   

adj.最年长的，最年老的

参考例句：

• The King's eldest son is the heir to the throne.国王的长子是王位的继承人。
• The castle and the land are entailed on the eldest son.城堡和土地限定由长子继承。

8 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

9 verge   

n.边，边缘；v.接近，濒临

参考例句：

• The country's economy is on the verge of collapse.国家的经济已到了崩溃的边缘。
• She was on the verge of bursting into tears.她快要哭出来了。

10 landmark   

n.陆标，划时代的事，地界标

参考例句：

• The Russian Revolution represents a landmark in world history.俄国革命是世界历史上的一个里程碑。
• The tower was once a landmark for ships.这座塔曾是船只的陆标。

11 resistant   

adj.(to)抵抗的，有抵抗力的

参考例句：

• Many pests are resistant to the insecticide.许多害虫对这种杀虫剂有抵抗力。
• They imposed their government by force on the resistant population.他们以武力把自己的统治强加在持反抗态度的人民头上。

12 racing   

n.竞赛，赛马；adj.竞赛用的，赛马用的

参考例句：

• I was watching the racing on television last night.昨晚我在电视上看赛马。
• The two racing drivers fenced for a chance to gain the lead.两个赛车手伺机竞相领先。

13 bind   

vt.捆，包扎；装订；约束；使凝固；vi.变硬

参考例句：

• I will let the waiter bind up the parcel for you.我让服务生帮你把包裹包起来。
• He wants a shirt that does not bind him.他要一件不使他觉得过紧的衬衫。

14 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

15 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。

16 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

17 entirely   

ad.全部地，完整地；完全地，彻底地

参考例句：

• The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
• His life was entirely given up to the educational work. 他的一生统统献给了教育工作。

18 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。

19 vomit   

v.呕吐，作呕；n.呕吐物，吐出物

参考例句：

• They gave her salty water to make her vomit.他们给她喝盐水好让她吐出来。
• She was stricken by pain and began to vomit.她感到一阵疼痛，开始呕吐起来。

20 bug   

n.虫子；故障；窃听器；vt.纠缠；装窃听器

参考例句：

• There is a bug in the system.系统出了故障。
• The bird caught a bug on the fly.那鸟在飞行中捉住了一只昆虫。

21 actively   

adv.积极地，勤奋地

参考例句：

• During this period all the students were actively participating.在这节课中所有的学生都积极参加。
• We are actively intervening to settle a quarrel.我们正在积极调解争执。

22 kit   

n.用具包，成套工具；随身携带物

参考例句：

• The kit consisted of about twenty cosmetic items.整套工具包括大约20种化妆用品。
• The captain wants to inspect your kit.船长想检查你的行装。

23 saliva   

n.唾液，口水

参考例句：

• He wiped a dribble of saliva from his chin.他擦掉了下巴上的几滴口水。
• Saliva dribbled from the baby's mouth.唾液从婴儿的嘴里流了出来。