Should people wear masks in public to slow the spread of sars-cov-2?
人们是否应该在公共场合戴口罩以减缓sars-cov-2的传播？
The World Health Organisation (WHO) says don’t bother. The British government agrees. America’s Centres for Disease Control and Prevention (CDC) initially discouraged it but by the beginning of April had reversed course. In parts of Asia, including China, it is baked into public behaviour and encouraged by health agencies, even when there is no ongoing public-health crisis. The issue? Whether or not members of the public should wear face-masks in a bid to slow the spread of SARS-COV-2, the virus responsible for the covid-19 pandemic.
翻译：
世界卫生组织说不需要费心（意思就是戴不戴都行，我觉得是这个意思）。英国政府表示同意这个说法。美国疾病预防控制中心一开始也不鼓励戴口罩，但是到4月初，情况已经逆转了。即使在没有持续的公共卫生危机的情况下，在包括中国在内的亚洲部分地区，戴口罩被纳入公众的行为中（感觉是在说戴口罩已经成为公众行为的一种习惯，bake是烘烤的意思）并受到卫生机构的鼓励。问题是什么呢？问题是人们是否应该戴上口罩以减慢SARS-COV-2的传播，这里SARS-COV-2（新冠病毒的官方名字）是导致covid-19的病毒。
单词：
in a bid to 为了
Understanding all the ways that SARS-COV-2 is transmitted is a matter of active scientific discussion. In the main, though, the virus hitches a ride on droplets of mucus or saliva that come out of the respiratory tracts of infected individuals. These may be expelled during normal breathing or, more commonly, as a cough that propels them a few metres into the air. Thus propelled, they may reach another person’s eyes, mouth or nose directly, and go on to infect cells in that individual’s airways. Or they may land on a surface, on which the virus particles they contain could survive for hours, or even days, and from which those particles may eventually be transferred to others who touch the surface and then touch their own face or mouth.
翻译：
理解SARS-COV-2的所有传播途径成为了一个火爆的科学讨论问题（这句话我翻译找不到合适的词来描述，感觉是在说这个新冠病毒传播的途径成为了科学界的一个焦点问题）。基本上，病毒会搭乘在从感染者呼吸道出来的粘液或唾液飞沫中（这里的hitch a ride非常有意思）。这些飞沫可能在正常呼吸时被排出，或者更为常见的是，通过咳嗽被推入空中好几米。因此，它们可能会直接到达他人的眼睛，嘴巴或鼻子，并继续感染这个人呼吸道中的细胞。或者它们可能会落在（物体的）表面上，其中包含的病毒颗粒可以存活数小时甚至数天，最终这些病毒颗粒可能会转移到接触了这些物体的表面然后摸了自己的脸或嘴的人。
单词：
hitch a ride 搭便车
mucus /‘mjuːkəs/ n. 粘液；黏液
saliva /sə’laɪvə/ n. 唾液；涎
tract /trækt/ n. （连通身体组织或器官的）道，束 比如the digestive tract 消化道
propel /prə’pel/ vt. 推进；驱使；驱策；激励
airway /‘eəweɪ/ n.气道
There is no doubt that masks form a barrier to transmission, by stopping droplets passing from infected to uninfected people close by. The WHO recommends standard surgical masks as part of the personal protective equipment to be worn by doctors and nurses who are caring for covid-19 patients in clinics and hospitals. The same goes for anyone caring for a patient at home. In most instances this is good enough, according to a meta-analysis of four randomised controlled trials that was published this month in Influenza by Mark Loeb of McMaster University, in Canada. Indeed, Dr Loeb found no significant differences between surgical masks and their more sophisticated cousins, N95 respirators, when it came to protecting health-care workers from viral infections transmitted by droplets—including those caused by coronaviruses.
翻译：
毫无疑问，口罩可以通过阻止飞沫从感染者传播到附近的未感染者来阻碍病毒传播。 WHO建议标准外科口罩由诊所和医院中护理covid-19患者的医生和护士佩戴，作为个人防护的一部分。对于在家中照顾病人的人也是这样。根据Mark Loeb本月在《流感》上发表的四项随机对照试验的综合分析，在大多数情况下这（标准外科口罩）就已经足够了。在保护医护人员免受飞沫传播的病毒（包括由冠状病毒引起的病毒感染）的感染时，Loeb发现，外科口罩与其更先进的表兄弟（哈哈哈哈妙啊这个表兄弟用的）N95之间没有显着差异。
单词：
meta-analysis /ˌmetəə'nælisis/
统计学上来说，元分析（meta-analysis，或译作后设分析、集成分析、综合分析、荟萃分析）是指将多个研究结果集成在一起的统计方法。就用途而言，它是文献回顾的新方法。
respirator /‘respɪreɪtə/ - n. 口罩,防毒面具 - (人工)呼吸机
This suggests that N95 respirators (which are thicker, more rigid, and designed to form a close seal around the nose and mouth) should be reserved for riskier situations. “N95” means they block at least 95% of particles smaller than 0.3 microns across. They are, therefore, appropriate for situations when the threat comes from objects smaller than exhaled droplets—meaning less than about five microns across. These particularly include times when doctors and nurses need to “intubate” a patient in an intensive care unit, by inserting the tube of a ventilator deep into that patient’s trachea. Intubation is a forceful procedure, and it creates aerosol particles (ie, smaller than five microns) that may carry viruses much farther through the air than droplets can manage. Though it remains unclear whether SARS-COV-2 is transmitted via aerosols in this way, those performing intubations should be cautious, says Lisa Brosseau, a respiratory-protection and infectious-diseases scientist at the University of Illinois at Chicago.
翻译：
这表明应将N95呼吸器（更厚，更坚固，并在鼻子和嘴周围形成紧密密封）用于风险更高的情况。 “N95”表示它们阻挡至少95％的小于0.3微米的颗粒。因此，它们适用于阻挡比呼出的飞沫还小的颗粒，即小于约5微米的颗粒。尤其是当医生和护士需要给重症监护室的病人“插管”的时候，即将呼吸机的管子深深插入该患者的气管中。气管插管是一个强制性的过程，它会形成气溶胶颗粒（即小于5微米），而气溶胶颗粒相对于飞沫来说可以通过空气将病毒传播得更远。芝加哥伊利诺伊大学呼吸保护和传染病科学家Lisa Brosseau说，尽管尚不清楚SARS-COV-2是否以这种方式通过气溶胶传播，但进行插管的人应谨慎行事。
Guidance for health-care workers is, therefore, clear: wear masks. Advice for members of the public has been more variable. Since the start of the outbreak the WHO and the CDC have advised people to avoid the use of masks unless they are in direct contact with symptomatic covid-19 patients. This is because such masks are a scarce resource. At the end of February Jerome Adams, America’s surgeon-general, beseeched his fellow citizens on Twitter to “seriously people—STOP BUYING MASKS!” because a run on them might cause supply problems for health-care workers.
翻译：
因此，对医护人员的指导很明确：戴口罩。而对公众的建议则更加变化无常。从疫情爆发以来，世卫组织和疾病预防控制中心建议人们，除非要直接与有症状的covid-19患者接触，其他情况不用戴口罩。因为这样子的口罩是稀缺资源。 2月底，美国卫生与公共服务部医务总监杰罗姆·亚当斯（Jerome Adams）在推特上恳求同胞们：“说真的大家——不要再买口罩了！”因为这种抢购现象可能会导致医疗工作者的供应问题。
单词：
trachea /ˈtreɪki:ə/ n. 气管,导管,螺旋纹管
intubate /‘ɪntjʊbeɪt/ vt. 把管子插进
forceful /‘fɔːsfʊl/ adj. 有说服力的；强有力的；坚强的
aerosol /‘eərəsɒl/ n. 喷雾器；气雾剂；浮质；气溶胶
beseech /bɪ’siːtʃ/ vt. 恳求；乞求(某事物)
A month or so later, the advice seems to be changing. The CDC now encourages the populace to wear homemade coverings for their mouths and noses. Dr Adams himself starred in an official video demonstrating how to use rubber bands around folded pieces of cloth to make DIY masks. Recently, the Czech Republic and Slovakia started requiring anyone stepping out into certain public places to use nose and mouth coverings. The same rule applies in Lombardy, in northern Italy, which was the centre of the covid-19 outbreak in that country. And Austria now requires masks in places such as supermarkets and pharmacies.
翻译：
一个月左右后，（戴不戴口罩的）建议似乎正在发生改变。 CDC现在鼓励民众戴自制的口罩，盖住口鼻。亚当斯（上面的美国卫生与公共服务部医务总监）本人曾出演官方视频，演示如何在折叠的布片周围使用橡皮筋制作口罩。最近，捷克共和国和斯洛伐克开始要求进入某些公共场合的人戴口罩。在意大利北部的Lombardy实施了相同的规定，Lombardy是意大利covid-19爆发的中心。现在奥地利的超市和药房等地方都需要人们佩戴口罩。
单词：
star /stɑː/ - vt. 用星号标于；由…主演，由…担任主角 - vi. 担任主角
rubber band 橡皮筋
The changing advice is testament to an evolving understanding of sars-cov-2 itself, and also to continuing debate among scientists about how far previous research on the effectiveness of masks can usefully be brought to bear on the current crisis.
翻译：
不断变化的建议证明了人们对SARS-COV-2的逐步理解。同样证明了对于之前口罩有效性的研究能多大程度上对现在的危机有用，科学家们一直争论不断。（这个真的太难理解了。）
句子分析：
and also后面的这半句话这么看： The changing advice is testament to continuing debate among scientists about (how far previous research on the effectiveness of masks 【can】 usefully be brought to bear on the current crisis.)
括号里可以这样看：how far …… can (usefully) be brought to bear on the current crisis. …能多大程度上对现在的危机有用
单词：
testament /'testəm(ə)nt/ n. 证据；证明 （同义词 testimony）
bring sth to bear (on sb/sth) 把精力用于；对…施加压力（或影响等）
例句：
1.We must bring all our energies to bear upon the task. 我们必须全力以赴不辱使命。
2.Pressure was brought to bear on us to finish the work ontime. 我们得按时完成工作，没有回旋余地。
It might seem intuitively obvious that having people cover their noses and mouths in public would be useful. In fact, the science of the matter is not clear-cut. Extrapolating to the laity the research which shows that masks and respirators are effective for those who work in health care is actually problematic.
翻译：
从直觉上看，让人们在公共场合遮住口鼻明显会很有用。而事实上，它的科学性还不那么明确。认为口罩和呼吸器对医疗工作者有效的研究，（但是将其结论）推断到普通民众的话实际上是有问题的。（意思是，对医疗工作者有效的话，不一定对普通民众也有效，下一段会解释原因）
句子分析：
Extrapolating to the laity the research which shows that masks and respirators are effective for those who work in health care is actually problematic.这句话最好这么分割，Extrapolating to the laity, the research（which shows that masks and respirators are effective for those who work in health care） is actually problematic.
单词：
intuitively /in'tju:itivli/ - adv. 直觉地;直观地
clear-cut /‘kliə'kʌt/ adj. 轮廓鲜明的,清晰的
extrapolate /ɪk’stræpəleɪt/ vt. (由已知资料对未知事实或价值)推算,推断
laity /‘leɪɪtɪ/ n. 俗人；外行人；门外汉
problematic /prɒblə’mætɪk/ - adj. 成问题的;有疑问的;阴暗的 - adv. 成问题地,有疑问地
One reason is that doctors and nurses are better-trained than others in how to wear these devices. For example, surgical masks work less well when they become moist, and so need to be replaced regularly throughout the day. Health-care workers will do this routinely. A member of the public might not. As to n95 respirators, they are notoriously difficult to fit in a way that seals them properly to a user’s face. Yet not fitting them correctly can negate their benefits—as can touching the front of a mask, or taking it off in the wrong way and so contaminating your hands.
翻译：
原因之一是医生和护士在如何佩戴这些设备方面比其他人受到了更好的培训。例如，外科口罩潮湿时效果不佳，因此需要全天定期更换。医疗工作者会定期做这件事。但公众可能不会。对于N95防护口罩，众所周知，很难以正确的方式将其密封到脸上。然而，不正确地佩戴N95会使其无效，触摸面罩的正面或以错误的方式脱掉口罩从而对手造成污染也是一样（让口罩变得没什么用）。
句子分析：
最后一句话 Yet not fitting them correctly can negate their benefits—as can touching the front of a mask, or taking it off in the wrong way and so contaminating your hands.其中的as 是“像……一样”，写完整应该是as 【touching the front of a mask, or taking it off in the wrong way and so contaminating your hands】 (can negate their benefits).就像是我们以前学的句子：They go to concerts frequently, as do I. 可以译为：他们经常去听音乐会，我也是。 也可译为：他们和我一样，经常去听音乐会。
单词：
negate /nɪ’geɪt/ - vt. 取消, 使无效 - 否定;否认
Nor do masks and respirators protect people’s eyes from virus particles. Only close-fitting goggles can do that. Finally, as Susan Michie, a health psychologist at University College London, observes, people might feel a false sense of security when wearing masks, and thus pay less attention to other important behaviours such as social distancing and handwashing.
口罩和呼吸器也不能保护人的眼睛免受病毒颗粒的侵害。只有紧的护目镜才能做到。最后，伦敦大学学院的健康心理学家Susan Michie观察到，人们戴着口罩时可能会感到虚假的安全感，因此很少注意其他重要行为，例如保持社交距离和洗手。
单词：
close-fitting /'kləuz,fitiŋ/ adj. 紧身的,贴身的
This does not, of course, show that masks for the public are of no use. A better way to think about them in this context might be that, rather than helping healthy people shield themselves from infection, they could be used to stop those who are already infected broadcasting the virus into the air around them. Given that much transmission of SARS-COV-2 is suspected to occur before someone who has the virus actually shows any symptoms (see follow- ing article), encouraging everyone to wear masks in public regardless of whether they are symptomatic could be a useful way to break the chain of transmission.
翻译：
当然，这并不表明为公众提供口罩是没有用的。在这种情况下，对它们进行思考的一种更好的方法可能是，它们可以用来阻止已经感染的人向周围的人传播病毒，而不是帮助健康的人免受感染。考虑到SARS-COV-2的大量传播可能是在被感染的人实际表现出任何症状之前发生的，鼓励所有人在公共场合戴口罩（无论其是否有症状）可能是一种打破传播链的有用的方法。
A study published in the current edition of Nature Medicine backs this idea up. Ben Cowling, an epidemiologist at Hong Kong University, measured the amount of virus shed, in half an hour of breaths and coughs, by participants infected with a variety of respiratory viruses, including influenza, rhinovirus and coronaviruses (though not sars-cov-2). In the case of those with coronaviruses, 30% of droplets and 40% of aerosol particles exhaled by participants without a surgical face-mask on contained virus particles. When they wore masks, that dropped to zero.
翻译：
最新版《自然医学》上发表的一项研究支持了这一想法。香港大学的流行病学家Ben Cowling测量了被几种不同的呼吸道病毒（包括流感，鼻病毒和冠状病毒）感染的人（虽然不是sars-cov-2）在半小时的呼吸和咳嗽中呼出的病毒数量。对于被冠状病毒感染的患者，没带外科口罩的参与者呼出的飞沫的30%和气溶胶颗粒的40%包含病毒。而当他们戴着口罩时，病毒含量降至零。
句子分析：
1.Ben Cowling, an epidemiologist at Hong Kong University, measured the amount of virus shed, （in half an hour of breaths and coughs插入语）, by participants infected with a variety of respiratory viruses, including influenza, rhinovirus and coronaviruses (though not sars-cov-2).
可以简化成这样： Ben Cowling measured the amount of virus shed by participants infected with a variety of respiratory viruses.
2.In the case of those with coronaviruses, 30% of droplets and 40% of aerosol particles （exhaled by participants without a surgical face-mask on）contained virus particles.
Rupert Beale, an infections biologist at the Francis Crick Institute in London, says that Dr Cowling’s study presents “strong and compelling” evidence in favour of the public wearing masks, but he warns that this approach should not be used in isolation. It could instead form part of a wider “exit strategy” from lockdown, combined with tried-and-tested measures including continued social distancing and thorough handwashing.
翻译：
伦敦弗朗西斯·克里克研究所（Francis Crick Institute）的感染生物学家鲁珀特·比尔（Rupert Beale）说，Dr. Cowling的研究给出了支持公众戴口罩的“有力且令人信服”的证据，但他警告说，这种方法不应孤立使用。取而代之的是，它可以构成更广泛的从封锁隔离“退出策略”的一部分，并结合久经考验的措施，包括持续的保持社交距离和彻底洗手。
单词：
compelling /kəmˈpelɪŋ/ - adj. 引人入胜的;扣人心弦的 - 非常强烈的;不可抗拒的 - 令人信服的，有说服力的
in isolation 单独地；孤立地
tried and tested 经过考验的；可靠的；可信赖的
This only works, though, if there are enough masks to go around. According to the WHO, “the chronic global shortage of personal protective equipment is now one of the most urgent threats to our collective ability to save lives. We must provide the protection health-care workers deserve to save our lives.”
翻译：
但是，这只有在有足够的口罩的情况下才有效。根据世界卫生组织的说法，“全球个人防护装备的长期短缺是目前我们共同拯救生命的最紧迫威胁之一。我们必须为医护人员提供应有的保护，以挽救我们的生命。”
单词：
go around 足够分给每个人；够每人一份
例句：There aren't enough chairs to go around. 椅子不够坐。
Which means that, if mask-wearing is to become a widespread weapon in the armory, members of the public may have to make their own. This is not as bad as it sounds. An experiment carried out in 2013 by Public Health England, that country’s health-protection agency, found that a commercially made surgical mask filtered 90% of virus particles from the air coughed out by participants, a vacuum cleaner bag filtered out 86%, a tea towel blocked 72% and a cotton T-shirt 51%—though fitting any DIY mask properly and ensuring a good seal around the mouth and nose is crucial.
翻译：
这意味着，如果口罩成为军械库中的一种普遍武器（不是很懂），公众可能必须自己制作（口罩）。这并不像听起来那样糟糕。英国公共卫生局于2013年进行的一项实验发现，商业生产的口罩可以过滤掉参与者咳嗽出的90％的病毒颗粒，用吸尘器袋可过滤掉86％，抹布能阻挡72％，棉质T恤能阻挡51％（然而正确佩戴任何自制口罩并确保口鼻周围的良好密封性至关重要。）
单词：
armoury /'ɑ:məri/ n. 兵工厂，军械库
vacuum cleaner 吸尘器；真空吸尘器；真空清洁器
tea towel n. （擦拭已洗餐具的）茶巾，抹布
Elaine Shuo Feng, an epidemiologist at Oxford University, has surveyed the varying advice given to members of the public around the world. In a commentary published recently in the Lancet Respiratory Medicine she and her colleagues argued that the absence of robust evidence on the public use of masks should not prevent precautionary action. It would be rational, they conclude, to recommend that people in quarantine who are not symptomatic wear face-masks if they need to leave home for any reason, in order to prevent potential asymptomatic or presymptomatic transmission if they unknowingly have the virus. Vulnerable populations, such as older adults and those with underlying medical conditions, should probably also wear face-masks if available.
翻译：
牛津大学的流行病学家Elaine Shuo Feng调查了向世界各地公众提供的各种建议。她和她的同事在《柳叶刀呼吸医学》上最近发表的一篇评书文章中指出，即使缺乏关于公众使用口罩的有力证据，也不能阻止预防措施的使用。他们得出结论的是，建议无症状的隔离人员如果出于某种原因需要离开家时要戴口罩，以防止在不知情的情况下有潜在的无症状或症状前传播。弱势群体，例如老年人和患有基础疾病的人群，也应戴口罩（如果有的话）。
单词：
rational /'ræʃ(ə)n(ə)l/ - adj. 理性的；合理的
asymptomatic /ə,sɪmptə’mætɪk/ adj. 无临床症状的
presymptomatic 症状发生前的
For everyone else, washing hands and maintaining social distance is the most important way to keep transmission down. Wearing masks in public does no harm, and may do some good—but that is always providing it does not reduce the supply available to local doctors and nurses.
翻译：
对于其他所有人来说，洗手并保持社交距离是降低传播的最重要方法。在公共场合戴口罩无害，并且可能有好处，但这始终应该在建立不减少当地医生和护士的口罩供给的基础上（意思是先保证医生和护士的医疗资源充足）。
单词：
providing /prə’vaɪdɪŋ/ conj. 如果；假如；在…条件下