近期新冠病毒奥密克戎变异株XBB.1.5在有些国家已经成为优势毒株，在我国也检测到了该毒株。XBB.1.5截至到目前所表现出来的特点有什么？致病力和毒性有变强吗？下面是卫报的一篇报道。
无注释原文：
Could new Omicron variant XBB.1.5 fuel further Covid infections?
Scientists have raised concerns about a new Covid variant that is spreading fast in the US and threatening to cause further waves of infection. Here’s what we know so far.
What is the new variant called?
It’s known as XBB.1.5. It’s one of the latest descendants of Omicron, the highly transmissible version of Covid that caused cases to surge in the UK last winter. Offshoots of Omicron have dominated global Covid infections ever since. XBB.1.5 evolved from the XBB variant of Omicron, itself a fusion of two different BA.2 variants.
How fast is it spreading?
The variant seems to have arisen in or around New York state in late October. At the end of December, the number of cases in the US more than doubled in a week. It now accounts for about 40% of all Covid infections in the US. Hospitalisations are rising in New York, raising fears that XBB.1.5 is about to cause further waves of illness as it spreads to other countries. Some US estimates suggest that XBB.1.5 is spreading more than twice as fast as the BQ.1.1 variant, which is one of the most common variants found in the UK.
Why is it spreading so rapidly?
The variant has an unusual mutation known as F486P that is helping it spread. The mutation changes part of the Covid virus that many antibodies from vaccination or previous infection target. The change makes the antibodies less effective at neutralising the virus. The parent variant, XBB, has a different mutation at the same position. This makes XBB good at evading immune defences too, but the mutation comes with a cost: the virus cannot latch on to human cells as effectively, so the virus is actually less infectious. The XBB.1.5 offshoot suffers no such handicap: the F486P mutation allows it to evade antibodies without compromising how well it attaches to human cells. In fact, it binds to them even more strongly than XBB, driving up its infectivity. “The mutation can give that immune evasion without the cost to infectivity and that’s why it’s become so successful,” says Ravi Gupta, professor of clinical microbiology at the University of Cambridge.
Does it cause more severe disease?
There is no evidence that XBB.1.5 causes more severe disease than other Omicron variants. But the fact that it is spreading fast is worrisome, as the virus is more likely to reach vulnerable people who could be hospitalised or die from the infection, especially if they have not received their latest booster.
Will it spark another wave?
That is the concern. In the US, scientists suspect XBB.1.5 is at least partly responsible for the rise in hospital admissions in New York, though cold weather and indoor gathering will also contribute. It is unclear whether the variant will drive a big surge in the UK, but some rise is anticipated. “It might drive an increase in cases, but I’m not convinced this will necessarily cause an explosive wave of infections in the UK,” says Gupta. “I don’t think there’s any cause to panic. The main thing we worry about is the severity of the disease, and there is no evidence that it’s more severe. People should, however, make sure they are up to date with their vaccines.”
Paradoxically, the winter wave of influenza and other nasty respiratory viruses that are doing the rounds might blunt any spike in Covid. If you catch a virus it should activate the innate immune system, the body’s frontline defences against pathogens, offering at least some protection against viruses that follow soon after. So if you caught flu or another respiratory virus over Christmas, your immune defences might resist a brief encounter with Covid.
What do scientists advise?
Vaccines are still the best way to protect against severe Covid, but Sam Wilson, a professor of virology at the University of Glasgow, says taking familiar Covid precautions will also help. “Regardless of the impact of a new variant, the NHS is already under tremendous pressure from a cocktail of different viruses this winter,” he says. “Where it is possible, taking voluntary steps to reduce transmission – reducing contacts, wearing high-quality masks in crowded indoor spaces, and isolating if you have symptoms – will help reduce the pressure on the NHS.”
注：中文文本为机器翻译，仅供参考
含注释全文：
Could new Omicron variant XBB.1.5 fuel further Covid infections?
From: The Guardian
Scientists have raised concerns about a new Covid variant that is spreading fast in the US and threatening to cause further waves of infection. Here’s what we know so far.
科学家们对一种新的新冠病毒变种表示担忧，这种变种正在美国迅速传播，并有可能引发进一步的感染潮。以下是我们目前所知道的。
concern
concern /kənˈsɜːrn/ 为名词，指「担心，忧虑」（a feeling of worry, especially one that is shared by many people）。raise concern about sth是一个固定搭配，指「表示担忧」。
例如：Many doctors have raised concerns about the drug. 许多医生对这种药表示担心。
这里raise也可替换为express或voice。
例如：Many people have voiced concern over the proposed changes in the law. 许多人就该法律所提议的改动表示了担心。
举个《经济学人》中的例子：Activists have long raised concerns about the poorly understood links between the environment and health. 长期以来，活动家们一直对人们对环境与健康之间的联系知之甚少表示担忧。
variant
variant /ˈveriənt/ 为名词，指「变种；变体」（a thing that is a slightly different form or type of something else）
例如：There are four variants of malaria, all transmitted to humans by a particular family of mosquitoes. 疟疾有4个变种，都是通过一种特殊的蚊子传播给人。
举个美剧《生活大爆炸》中的例子：
What is the new variant called?
It’s known as XBB.1.5. It’s one of the latest descendants of Omicron, the highly transmissible version of Covid that caused cases to surge in the UK last winter. Offshoots of Omicron have dominated global Covid infections ever since. XBB.1.5 evolved from the XBB variant of Omicron, itself a fusion of two different BA.2 variants.
新变种叫什么？
它被称为 XBB.1.5，是 Omicron 的最新后代之一。Omicron 是新冠的高传染性变体，去年冬天导致英国病例激增。从那时起，Omicron 的分支就主导了全球新冠感染。XBB.1.5 从 Omicron 的 XBB 变体演变而来，它本身是两个不同 BA.2 变体的融合。
descendant
descendant /dɪˈsendənt/ 为名词，指「派生物；后代」（something that has developed from something similar in the past）
例如：Recent evidence supports the theory that birds are the modern descendants of dinosaurs.近期的证据为鸟类是恐龙的现代后裔这一理论提供了支持。
transmissible
transmissible /trænsˈmɪsəbəl/为形容词，指「可传播的；可传染的」（able to be spread to other people, animals, etc. : capable of being transmitted）
例如：The virus is highly transmissible to/among humans.这种病毒很容易传染给人/在人群中传播。
举个《经济学人》中的例子：It is far more transmissible than previous variants, and has driven its predecessors towards extinction around the world in just one month. 它比以前的变种更容易传播，并在短短一个月内将其前身推向了世界范围内的灭绝。
surge
surge /sɜːrdʒ/ 为动词，指「陡增，剧增，急剧上升」（to suddenly increase to an unusually high level）
例如：Housing prices have surged in recent months.最近几个月房价飞涨。
举个《经济学人》中的例子：When oil prices surge, growth typically moves in the opposite direction.当油价飙升时，增长通常会朝相反的方向发展。
也可作名词，后面加介词in，例如：There has been a surge in house prices recently.最近房价飞涨。
offshoot
offshoot /ˈɔːfʃuːt/ 为名词，指「分支；分支机构」（something such as an organization which has developed from a larger or earlier one）
例如：It's an offshoot of a much larger company based in Sydney.这是总部设在悉尼的一家规模更大的公司的分支机构。
dominate
dominate /ˈdɑːmɪneɪt/ 为动词，指「在…中占首要地位，在…中最具影响力」（to dominate a situation means to be the most powerful or important person or thing in it.）
例如：The elections continue to dominate the headlines. 选举继续占据头条。
fusion
fusion /ˈfjuːʒn/ 为名词，指「融合，结合」（the process or result of joining two or more things together to form one）后面通常加介词 of。
例如：The movie displayed a perfect fusion of image and sound.这部电影展示了影像与音响的完美结合。
How fast is it spreading?
The variant seems to have arisen in or around New York state in late October. At the end of December, the number of cases in the US more than doubled in a week. It now accounts for about 40% of all Covid infections in the US. Hospitalisations are rising in New York, raising fears that XBB.1.5 is about to cause further waves of illness as it spreads to other countries. Some US estimates suggest that XBB.1.5 is spreading more than twice as fast as the BQ.1.1 variant, which is one of the most common variants found in the UK.
它的传播速度有多快？
该变种似乎于 10 月下旬在纽约州或其周边地区出现。到 12 月底，美国的病例数在一周内翻了一番多。它现在约占美国所有新冠感染病例的 40%。纽约的住院人数正在上升，这引发了人们对 XBB.1.5 在传播到其他国家时将引发更多疾病浪潮的担忧。美国的一些估计表明，XBB.1.5 的传播速度是 BQ.1.1 变体的两倍多，BQ.1.1 变体是在英国发现的最常见的变体之一。
hospitalisation
hospitalisation /ˌhɑːspɪtələˈzeɪʃn/ 为名词，也可以写作hospitalization，指「住院治疗」（the act of taking someone to hospital and keeping them there for treatment）
例如：Her injuries were not serious enough to require hospitalization.她的伤势还没严重到需要住院治疗的地步。
其动词形式为 hospitalize，表示「送〔某人〕入院治疗」（to send somebody to a hospital for treatment），通常用被动语态。
例如：She needs to be hospitalized immediately. 她需要立即入院治疗。
举个美剧《无耻之徒》中的例子：
Why is it spreading so rapidly?
The variant has an unusual mutation known as F486P that is helping it spread. The mutation changes part of the Covid virus that many antibodies from vaccination or previous infection target. The change makes the antibodies less effective at neutralising the virus. The parent variant, XBB, has a different mutation at the same position. This makes XBB good at evading immune defences too, but the mutation comes with a cost: the virus cannot latch on to human cells as effectively, so the virus is actually less infectious. The XBB.1.5 offshoot suffers no such handicap: the F486P mutation allows it to evade antibodies without compromising how well it attaches to human cells. In fact, it binds to them even more strongly than XBB, driving up its infectivity. “The mutation can give that immune evasion without the cost to infectivity and that’s why it’s become so successful,” says Ravi Gupta, professor of clinical microbiology at the University of Cambridge.
为什么它传播得如此之快？
该变体有一个不寻常的突变，称为 F486P，有助于它传播。这种突变改变了新冠病毒的一部分，许多来自疫苗接种或先前感染的抗体都以该部分为目标。这种变化使抗体对抗病毒的效果降低。父变体 XBB 在同一位置具有不同的突变。这使得 XBB 也擅长逃避免疫防御，但这种突变是有代价的：病毒无法有效地粘附人体细胞，因此病毒实际上具有较低的传染性。XBB.1.5 分支没有这样的障碍：F486P 突变使它能够逃避抗体，而不会影响它与人类细胞的结合程度。事实上，它与细胞的结合比 XBB 更强，从而提高了它的传染性。剑桥大学临床微生物学教授拉维·古普塔 (Ravi Gupta) 说：“这种突变可以在不以传染性为代价的情况下提供免疫逃避，这就是它变得如此成功的原因。”
mutation
mutation /mjuːˈteɪʃn/ 为名词，表示「突变，变异」（a change in the genetic structure of an animal or plant that makes it different from others of the same kind）
例如：The disease is caused by genetic mutations.这种疾病是由基因突变所致。
其动词形式为mutate，表示「（使）变异，突变」（to develop or make something develop a new form or structure, because of a genetic change）
例如：These bacteria have mutated into forms that are resistant to certain drugs.这些细菌已发生变异，对某些药物产生了抗药性。
antibody
antibody /ˈæntibɑːdi/ 为名词，表示「抗体」（a substance that the body produces in the blood to fight disease, or as a reaction when certain substances are put into the body）
例如：Antibodies found in breast milk protect newborn babies against infection.母乳中含有的抗体可保护新生婴儿免受感染。
neutralise
neutralise /ˈnuːtrəlaɪz/ 为动词，表示「使失效，抵消」（to stop something from having any effect）
例如：Rising prices neutralize increased wages.不断上涨的物价会抵消工资的增长。
latch on to
latch on to 或者为 latch onto，表示「依附；黏附」（if one thing latches onto another, or if it latches on, it attaches itself to it and becomes part of it）
例如：These are substances which specifically latch onto the protein on the cell membrane. 这些物质专门依附在细胞膜的蛋白质之上。
handicap
handicap /ˈhændikæp/为名词，表示「障碍；不利因素」（something that makes it difficult for somebody to do something）
例如：Not speaking the language proved to be a bigger handicap than I'd imagined.事实证明，不会讲这种语言所造成的障碍比我想象的大。
evade
evade /ɪˈveɪd/ 为动词，表示「逃脱；躲开；躲避」（to avoid or escape from someone or something）
例如：He managed to evade capture.他设法逃脱了抓捕。
其名词为 evasion /ɪˈveɪʒn/，我们常说的逃税就是tax evasion
例如：She's been charged with tax evasion.她被控逃税。
Does it cause more severe disease?
There is no evidence that XBB.1.5 causes more severe disease than other Omicron variants. But the fact that it is spreading fast is worrisome, as the virus is more likely to reach vulnerable people who could be hospitalised or die from the infection, especially if they have not received their latest booster.
它会导致更严重的疾病吗？
没有证据表明 XBB.1.5 导致的疾病比其他 Omicron 变体更严重。但它传播迅速的事实令人担忧，因为该病毒更有可能影响那些可能因感染而住院或死亡的弱势群体，尤其是如果他们没有打加强剂的情况下。
worrisome
worrisome /ˈwɜːrisəm/ 为形容词，表示「令人担心的；使人担忧的」（causing people to worry）
例如：Alcohol and tobacco consumption by young people is especially worrisome because habits formed early are likely to persist.年轻人的吸烟饮酒问题特别令人担心，因为那些早期形成的习惯很可能持续下去。
举个美剧《豪斯医生》中的例子：
Will it spark another wave?
That is the concern. In the US, scientists suspect XBB.1.5 is at least partly responsible for the rise in hospital admissions in New York, though cold weather and indoor gathering will also contribute. It is unclear whether the variant will drive a big surge in the UK, but some rise is anticipated. “It might drive an increase in cases, but I’m not convinced this will necessarily cause an explosive wave of infections in the UK,” says Gupta. “I don’t think there’s any cause to panic. The main thing we worry about is the severity of the disease, and there is no evidence that it’s more severe. People should, however, make sure they are up to date with their vaccines.”
会不会掀起另一波浪潮？
这就是问题所在。在美国，科学家们怀疑 XBB.1.5 至少是纽约住院人数上升的部分原因，尽管寒冷的天气和室内聚集也是致病因素。目前尚不清楚该变体是否会导致英国的病例激增，但预计会有所上升。古普塔说：“这可能会导致病例增加，但我不相信这必然会在英国引起大规模的感染潮。我认为没有任何恐慌的理由。我们主要担心的是疾病的严重程度，没有证据表明它更严重。然而，人们应该确保自己接种了最新的疫苗。”
admission
admission /ədˈmɪʃn/ 为名词，表示「入院治疗﹐收治」（the process of taking someone into a hospital for treatment, tests, or care）
例如：There are 13,000 hospital admissions annually due to playground accidents.每年有13,000人因为游乐场上的意外而入院治疗。
contribute
contribute /kənˈtrɪbjuːt/ 为动词，这里不是指「捐助」，而是表示「促成;促使；是导致…的原因之一」（to be one of the causes of something），后面通常加介词 to
例如：Several factors may be contributing to the fall in the number of applicants.几个因素可能是申请人数下降的原因。
necessarily
necessarily /ˌnesəˈserəli/ 为副词，表示「必然地；不可避免地」（used to say that something cannot be avoided）
例如：Public spending necessarily affects the economy. 公共开支必然影响经济。
当与not连用时，表示「不一定；未必」（possibly but not certainly — used to say that something is not definitely true）
例如：Expensive restaurants aren’t necessarily the best.昂贵的餐馆不一定是最好的。
Paradoxically, the winter wave of influenza and other nasty respiratory viruses that are doing the rounds might blunt any spike in Covid. If you catch a virus it should activate the innate immune system, the body’s frontline defences against pathogens, offering at least some protection against viruses that follow soon after. So if you caught flu or another respiratory virus over Christmas, your immune defences might resist a brief encounter with Covid.
矛盾的是，冬季流行的流感和其他正在流行的令人讨厌的呼吸道病毒可能会减缓新冠病例的激增。如果你感染了病毒，它会激活免疫系统。这是人体抵御病原体的前线防御系统，至少可以提供一些保护来抵御紧随其后的病毒。因此，如果您在圣诞节期间感染了流感或其他呼吸道病毒，您的免疫防御系统可能会抵御感染的新冠病毒。
respiratory
respiratory /ˈrespərətɔːri/ 为形容词，表示「呼吸的」（connected with breathing）
例如：Smoking can cause respiratory diseases.吸烟会导致呼吸系统疾病。
do the rounds
do the rounds 表示「到处传播」（to go from one person or place to another）
例如：This virus seems to be doing the rounds at the moment.
What do scientists advise?
Vaccines are still the best way to protect against severe Covid, but Sam Wilson, a professor of virology at the University of Glasgow, says taking familiar Covid precautions will also help. “Regardless of the impact of a new variant, the NHS is already under tremendous pressure from a cocktail of different viruses this winter,” he says. “Where it is possible, taking voluntary steps to reduce transmission – reducing contacts, wearing high-quality masks in crowded indoor spaces, and isolating if you have symptoms – will help reduce the pressure on the NHS.”
科学家们有什么建议？
疫苗仍然是预防严重新冠的最佳方法，但格拉斯哥大学病毒学教授 Sam Wilson 说，采取常见的新冠预防措施也会有所帮助。“不管新变种的影响如何，今年冬天 NHS 已经承受着来自不同病毒混合物的巨大压力，”他说。“在可能的情况下，自主采取措施减少传播——减少接触，在拥挤的室内空间戴上高质量的口罩，如果有症状就隔离——将有助于减轻 NHS 的压力。”
vaccine
vaccine /vækˈsiːn/ 为名词，指「疫苗」（a substance that is put into the blood and that protects the body from a disease）
例如：There is no vaccine against HIV infection.现在还没有防止感染艾滋病病毒的疫苗。
cocktail
cocktail /ˈkɑːkteɪl/ 为名词，但在这里不是指鸡尾酒，而是表示「混合物」（a mixture of different things）
例如：The disease is being treated with a cocktail of powerful drugs.现在正通过将多种强效药物混合起来治疗这一疾病。
NHS
NHS是National Health Service的缩写，指「国民医疗保健系统」，是英国靠税收维持的公众医疗服务，通常搭配介词on
例如：I had the operation done on the NHS (= paid for by the NHS).我做这次手术是国民医疗服务体系资助的。
再如：An increasing number of these treatments are now available on the National Health Service. 现在越来越多这样的治疗项目已纳入国民医疗保健系统。