「雅思阅读素材」New Scientist 210123

Can coronavirus variants reinfect people and evade the vaccines?

新冠病毒的变体是否会让人再次感染，或让疫苗失效？

SOON after vaccination began in many countries, reports of faster-spreading coronavirus variants triggered fears that vaccines might not protect against them. The good news is that initial studies suggest that the existing shots will still work, although they might be slightly less effective against two variants, one that emerged in South Africa and one from Brazil.

“I am optimistic that current vaccines will remain quite useful,” says Jesse Bloom at the Fred Hutchinson Cancer Research Center in Seattle. “But I do expect that eventually it will be necessary to update vaccines to account for viral evolution.”

variants: 变体

shot：注射，是一个比较informal的用法，短语可以说give sb a shot. 除了指扎针这种注射之外，也可以引申出来抽象含义，比如

The improved trade figures are a much-needed shot in the arm for the economy. 贸易数字的改善为经济打了一剂急需的强心针。

viral evolution：病毒进化

Antibodies are our main defence against viruses. When we get infected by a new virus, our immune system starts producing a range of antibodies that bind to various parts of viral proteins.

Not all antibodies are equal. Studies show that only a few antibodies can “neutralise” viruses and prevent infections. These neutralising antibodies bind to key sites on viral proteins.

produce antibodies that bind to parts of viral proteins: 产生抗体，与病毒蛋白结合

neutralise：抵消，中和

For the coronavirus, one such site is the part of its so-called spike protein that binds to receptors on human cells and helps the virus get inside – the receptor binding domain. If this part of the spike protein changes, neutralising antibodies may not bind as well.

spike protein：刺突蛋白

receptors：受体

大意：新冠病毒发生变异，影响了它的刺突蛋白，这种蛋白会与人体细胞的受体结合，从而让病毒进入人体。但如果这种刺突蛋白发生变化，抗体可能就不能起作用。

A rapidly spreading variant named B.1.1.7, first spotted in the UK, has only one mutation that affects this binding domain. Initial studies of antibodies from those previously infected by the coronavirus or given the Pfizer and BioNTech vaccine show little or no drop in effectiveness against B.1.1.7.

mutation：突变，指的是在结合处发生了一出突变

BioNTech：德国的生物科技公司

大意：对于B.1.1.7这种变体，疫苗的有效程度几乎不受影响。

The variant from South Africa, called B.1.351, is of more concern. It has three mutations in the binding domain, including one named E484K as it occurs at a site called E484. The variant from Brazil, known as P.1, has almost the same three mutations.

According to a computer model, B.1.351’s spread can be explained by this variant being 50 per cent more transmissible or 20 per cent better at evading immunity in previously infected people, when compared with previous variants. Lab studies point to the latter.

transmissible：可传染的，通常指disease。也可以指可传输的信息、能量等。

大意：电脑模型显示这种变体要么是更易传染，要么更容易被再次感染；实验显示结果是后者。

Bloom and his team have tested how mutations in the binding domain alter the effectiveness of antibodies from people who have been infected with the coronavirus. Mutations at the E484 site made the biggest difference, with neutralising activity falling as much as tenfold.

While that sounds alarming, current vaccines work so well that even a big drop in neutralisation might not substantially reduce protection, says Bloom. The antibodies might not be as effective, but they still get the job done. There were also differences between individuals: antibodies from some worked just as well.

tenfold：十倍，可以做形容词或副词，比如a tenfold increase/increase tenfold

大意：E484这处地方的突变，会让抗体的中和功能下降十倍

More evidence comes from a study by Rino Rappuoli at GlaxoSmithKline Vaccines in Italy. When his team grew the virus in the presence of antibodies from a previously infected person, E484K was one of three mutations that let the virus become resistant.

resistant: 抗...的，一般用于指病毒或某种材料，比如resistant to virus抗病毒的, waterresistant防水的

These findings suggest that the spread of B.1.351 and P.1 is due to the E484K mutation helping the virus evade antibodies and reinfect people who have already had covid-19. “Whether on top of this they are more infectious, I don’t know,” says Rappuoli.

（这位研究者说，即使这种变体会让人再次感染，但也并不能说明它的传染力就更强...十分严谨了）

There have been reports of reinfections in South Africa, government epidemiologist Salim Abdool Karim said in an online presentation. There has also been a report of a woman in Brazil having more severe symptoms the second time round. But such anecdotal reports are to be expected, said Karim, and in South Africa there is no evidence of a systematic rise in reinfections.

epidemiologist：流行病学家，构词是epidemiology流行病学+ist

severe symptoms：严重的症状，与symptom搭配一般用serious/severe

to be expected: 在意料之中的

This could be because testing how well antibodies neutralise viruses outside the body doesn’t tell the whole story. The so-called T-cell response is also important. T-cells spot an infected cell by detecting viral proteins on its surface, and then destroy it before it releases more viruses.

“T-cells can be incredibly valuable at preventing disease,” says Shane Crotty at the La Jolla Institute for Immunology in California. “They can do it so well that the person never gets sick.” Crucially, an effective T-cell response only requires the recognition of viral proteins, rather than the blocking of their function. This means it is harder for resistance to evolve because no one site is crucial.

T-cell response: 不确定这个应该怎么翻译，指的应该是一种免疫过程

the recognition of viral proteins：病毒蛋白的识别

The T-cell response to the coronavirus is broad, involving many parts of the spike protein as well as other proteins. “There is no way these variants are escaping T-cell immunity,” says Crotty. Unfortunately, while T-cells can stop people getting symptoms, they cannot prevent infections.

大意：这种免疫过程只会让人们不显现症状，但并不会阻止感染

The bottom line is that existing vaccines should still protect against B.1.351 and P.1, but might be slightly less effective. And there is a danger of these variants or others evolving to be much better at evading vaccine protection.

This means we need to step up surveillance so we can spot any such “escape variants” early and have time to update vaccines, says Angela Rasmussen at Georgetown University in Washington DC.

bottom line: 底线，关键

step up surveillance: step up在这里表示增加，比如step up one's efforts to do sth更加努力做某事。也有向前走的意思。surveillance，监视，keep sb under surveillance 对某人实施监视

evading vaccine：表示病毒不受疫苗的控制，这里用到了evade逃脱，还有escape，感觉比较生动

“It is unlikely that, overnight, a variant is going to emerge that is capable of completely evading the vaccine,” she says. “But if we are not looking, then we might not find them until it’s too late.”

Scientists are already looking at how to update the vaccines and it will be relatively easy to update most of them. The main delay could be getting them approved. New Scientist asked regulators in the UK, US and Europe what manufacturers would need to do. None has yet decided on the process, but some pointed to the updating of seasonal flu vaccines as a possible precedent. Updated flu vaccines don’t have to undergo clinical trials, so the process could be rapid. “I believe it can be done very quickly,” says Rappuoli.

getting them approved：使其被批准/赞成

regulators：监管者

seasonal flu vaccines：季节性流感疫苗

precedent：范例，先例，比如set/create a precedent 开创先例。这个词并不指前辈/古人这种意思（发现我一直搞混了） 如果指古人，可以用predecessor/ancestor/antecedent

clinical trials：临床试验

Read more: 

https://www.newscientist.com/article/2265221-can-coronavirus-variants-reinfect-people-and-evade-the-vaccines/#ixzz6kl3Mu1kh