curated by Marilyn M.Singleton,M.D.,J.D.
由玛丽莲·m·辛格尔顿博士和法学博士共同策划。
Transmission of SARS-CoV-2
SARS-CoV-2的传播
Note:A COVID-19(SARS-CoV-2)particle is 0.125 micrometers(μm);influenza virus size is 0.08–0.12μm;a human hair is about 150μm.
注:一个新型冠状病毒肺炎(SARS-CoV-2)颗粒为0.125微米，流感病毒大小为0.08-0.12微米，人类头发约为150微米。
*1 nm=0.001 micron;1000 nm=1 micron;Micrometer(μm)is the preferred name for micron(an older term)
*1纳米=0.001微米;1000纳米=1微米;微米(m)是微米(一个较早的术语)的首选名称
1 meter is=1,000,000,000 nm or 1,000,000 microns
1米=1,000,000,000 nm 或1,000,000微米
Droplets
液滴
Virus is transmitted through respiratory droplets produced when an infected person coughs,sneezes or talks.Larger respiratory droplets(>5μm)remain in the air for only a short time and travel only short distances,generally<1 meter.They fall to the ground quickly.
病毒通过感染者咳嗽、打喷嚏或说话时产生的呼吸道飞沫传播。较大的呼吸飞沫(大于5微米)在空气中停留的时间很短，而且飞行距离很短，一般小于1米。他们很快就倒在地上
https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30245-9/fulltext
This idea guides the CDC's advice to maintain at least a 6-foot distance.
这个想法指导 CDC 的建议保持至少6英尺的距离
Virus-laden small(<5μm)aerosolized droplets can remain in the air for at least 3 hours and travel long distances.
携带病毒的雾化小液滴可以在空气中停留至少3个小时，并且可以飞行很长的距离
https://www.nejm.org/doi/pdf/10.1056/NEJMc2004973?articleTools=true
Air currents
气流
In air conditioned environment these large droplets may travel farther.
在空调环境中，这些大液滴可以飞得更远
However,ventilation—even the opening of an entrance door and a small window can dilute the number of small droplets to one half after 30 seconds.(This study looked at droplets from uninfected persons).This is clinically relevant because poorly ventilated and populated spaces,like public transport and nursing homes,have high SARS-CoV-2 disease transmission despite physical distancing.
然而，通风ーー即使是打开入口门和小窗户，也可以在30秒后稀释小水滴的数量，使其减少一半。(这项研究观察了来自未感染者的飞沫)。这具有临床相关性，因为尽管物理距离较远，但通风不良和人口密集的空间，如公共交通和疗养院，有较高的 SARS-CoV-2疾病传播https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30245-9/fulltext
Objects and surfaces
物体和表面
Person to person touching
人与人之间的接触
The CDC's most recent statement regarding contracting COVID-19 from touching surfaces:"Based on data from lab studies on Covid-19 and what we know about similar respiratory diseases,it may be possible that a person can get Covid-19 by touching a surface or object that has the virus on it and then touching their own mouth,nose or possibly their eyes,"the agency wrote."But this isn't thought to be the main way the virus spreads.
疾病防治中心最近关于接触表面感染新型冠状病毒肺炎病毒的声明中写道:"根据对新型冠状病毒肺炎病毒的实验室研究数据和我们对类似呼吸道疾病的了解，有可能一个人通过接触表面或物体上的病毒，然后触摸自己的嘴、鼻子或者可能是他们的眼睛而感染新型冠状病毒肺炎病毒。"。"但这并不是病毒传播的主要方式
https://www.cdc.gov/media/releases/2020/s0522-cdc-updates-covid-transmission.html.
Chinese study with data taken from swabs on surfaces around the hospital
中国一项研究的数据来自医院周围表面的拭子
https://wwwnc.cdc.gov/eid/article/26/7/20-0885_article?deliveryName=USCDC_333-DM25707
The surfaces where tested with the PCR(polymerase chain reaction)test,which greatly amplifies the viral genetic material if it is present.That material is detectable when a person is actively infected.This is thought to be the most reliable test.
表面测试的 PCR(聚合酶链式反应)检测，这大大增强了病毒的遗传物质，如果它是存在的。当一个人被主动感染时，这种物质是可以检测到的。这被认为是最可靠的测试
Computer mouse(ICU 6/8,75%;General ward(GW)1/5,20%)
电脑鼠标(ICU 6/8,75%;普通病房(GW)1/5,20%)
Trash cans(ICU 3/5,60%;GW 0/8)
垃圾桶(ICU 3/5,60%;GW 0/8)
Sickbed handrails(ICU 6/14,42.9%;GW 0/12)
病床扶手(ICU 6/14,42.9%;GW 0/12)
Doorknobs(GW 1/12,8.3%)
门把手(GW 1/12,8.3%)
81.3%of the miscellaneous personal items were positive:
81.3%的杂项个人物品是正面的:
Exercise equipment
运动器材
Medical equipment(spirometer,pulse oximeter,nasal cannula)
医疗器械(肺活量计、脉搏血氧计、鼻腔插管)
PC and iPads
个人电脑和 ipad
Reading glasses
阅读眼镜
Cellular phones(83.3%positive for viral RNA)
手机(83.3%的病毒 RNA 阳性)
Remote controls for in-room TVs(64.7%percent positive)
室内电视的遥控器(64.7%为阳性)
Toilets(81.0%positive)
厕所(81.0%正面)
Room surfaces(80.4%of all sampled)
房间表面(80.4%的采样)
Bedside tables and bed rails(75.0%)
床头柜和床扶手(75.0%)
Window ledges(81.8%)
窗台(81.8%)
Plastic:up to 2-3 days
塑料袋:最多2-3天
Stainless Steel:up to 2-3 days
不锈钢:最多2-3天
Cardboard:up to 1 day
硬纸板:最多1天
Copper:up to 4 hours
铜:长达4小时
Floor–gravity causes droplets to fall to the floor.Half of ICU workers all had virus on the bottoms of their shoes
地面引力导致水滴落到地面。一半的重症监护室工作人员的鞋底都有病毒
Filter Efficiency and Fit
过滤器的效率和适应性
*Data from a University of Illinois at Chicago review
*数据来自美国伊利诺大学芝加哥分校协会审查
HEPA(high efficiency particulate air)filters–99.97–100%efficient.HEPA filters are tested with particles that are 0.125μm.
高效微粒空气过滤器-99.97-100%有效率。高效微粒空气过滤器的测试粒子为0.125米
Masks and respirators work by collecting particles through several physical mechanisms,including diffusion(small particles)and interception and impaction(large particles)
口罩和防护口罩通过几种物理机制收集粒子，包括扩散(小颗粒物)和拦截和阻塞(大颗粒物)
N95 filtering facepiece respirators(FFRs)are constructed from electret(a dielectric material that has a quasi-permanent electric charge.An electret generates internal and external electric fields so the filter material has electrostatic attraction for additional collection of all particle sizes.As flow increases,particles will be collected less efficiently.
N95过滤面罩式呼吸器(FFRs)由驻极体(一种具有准永久电荷的介质材料)构成。驻极体产生内部和外部电场，因此过滤材料具有静电吸引力，可以收集所有粒径的额外粒子。随着流量的增加，颗粒的收集效率会降低
N95–A N95-aproperly fitted
合适的装配 N95 will block 95%of tiny air particles down to 0.3μm from reaching the wearer's face
.N95可以阻挡95%的微小空气颗粒到达0.3微米以下的佩戴者的脸部https://www.honeywell.com/en-us/newsroom/news/2020/03/n95-masks-explained.
But even these have problems:many have exhalation valve for easier breathing and less moisture inside the mask.
但即使这些也有问题:许多人有呼气阀，以便于呼吸，减少面膜内的水分
Surgical masks are designed to protect patients from a surgeon's respiratory droplets,aren't effective at blocking particles smaller than 100μm.
医用口罩是为了保护病人免受外科医生的呼吸道飞沫的伤害而设计的，对于100微米以下的颗粒无效
https://webcache.googleusercontent.com/search?q=cache:VLXWeZBll7YJ:https://multimedia.3m.com/mws/media/957730O/respirators-and-surgical-masks-contrast-technical-bulletin.pdf+&cd=13&hl=en&ct=clnk&gl=us
Filter efficiency was measured across a wide range of small particle sizes(0.02 to 1µm)at 33 and 99 L/min.
在33和99l/min 的范围内，测量了不同粒径(0.02ー1 m)的过滤效率
N95 respirators had efficiencies greater than 95%(as expected).N95
呼吸防护口罩的效率高于95%(如预期)
T-shirts had 10%efficiency,
T 恤衫有10%的效率,
Scarves 10%to 20%,
围巾10%到20%,
Cloth masks 10%to 30%,
10%到30%的面料,
Sweatshirts 20%to 40%,and 20%至40%，
Towels 40%.
毛巾40%
All of the cloth masks and materials had near zero efficiency at 0.3µm,a particle size that easily penetrates into the lungs.
所有的布面具和材料在0.3微米处的效率接近于零，这种粒子大小很容易穿透到肺部
Another study evaluated 44 masks,respirators,and other materials with similar methods and small aerosols(0.08 and 0.22µm).
另一项研究评估了44种口罩、呼吸器和其他使用类似方法的材料以及小型气溶胶(0.08米和0.22米)
N95 FFR filter efficiency was greater than 95%
.N95 FFR 过滤效率大于95%
Medical masks–55%efficiency
医用口罩-效率55%
General masks–38%and
一般口罩-38%及
Handkerchiefs–2%(one layer)to 13%(four layers)efficiency.
手帕-2%(一层)至13%(四层)效率
Conclusion:Wearing masks will not reduce SARS-CoV-2.
结论:戴口罩不会减少 SARS-CoV-2
N95 masks protect health care workers,but are not recommended for source control transmission.
N95口罩保护医护人员，但不推荐用于源头控制传播
Surgical masks are better than cloth but not very efficient at preventing emissions from infected patients.
外科口罩比布料好，但在防止受感染病人排放物方面效果不是很好
Cloth masks will be ineffective at preventing SARS-CoV-2 transmission,whether worn as source control or as personal protective equipment(PPE).
无论是作为源头控制还是作为个人防护设备(PPE)佩戴，口罩在防止 sarsーcov-2传播方面都是无效的
"Masks may confuse that message and give people a false sense of security.If masks had been the solution in Asia,shouldn't they have stopped the pandemic before it spread elsewhere?"
"面具可能会混淆信息，给人们一种错误的安全感。如果口罩在亚洲是解决问题的办法，难道他们不应该在大流行传播到其他地方之前阻止它吗?"
*The first randomized controlled trial of cloth masks.https://bmjopen.bmj.com/content/5/4/e006577
*第一个戴面具的随机对照试验
Penetration of cloth masks by particles was 97%and medical masks 44%,3M Vflex 9105 N95(0.1%),3M 9320 N95(<0.01%).
粒子渗透率为97%，医用口罩为44%，3M Vflex 9105n95(0.1%)，3M 9320n95(<0.01%)
Moisture retention,reuse of cloth masks and poor filtration may result in increased risk of infection.
保湿、重复使用布面具和过滤不良可能会增加感染的风险
The virus may survive on the surface of the face-masks
病毒可以在面罩表面存活
Self-contamination through repeated use and improper doffing is possible.A contaminated cloth mask may transfer pathogen from the mask to the bare hands of the wearer.
重复使用和不当落纱可能造成自身污染。受污染的布质面具可能会将病原体从面具传播到佩戴者的手上
Cloth masks should not be recommended for health care workers,particularly in high-risk situations,and guidelines need to be updated.
不建议医护人员使用口罩，特别是在高危情况下，并且需要更新指南
*A study of 4 patients in South Korea
*一项有关韩国四名病人的研究
https://www.acpjournals.org/doi/10.7326/M20-1342
Known patients infected with SARS-CoV-2 wore masks and coughed into a Petrie dish."Both surgical and cotton masks seem to be ineffective in preventing the dissemination of SARS–CoV-2 from the coughs of patients with COVID-19 to the environment and external mask surface."
已知感染 SARS-CoV-2的病人戴着口罩，咳嗽时使用 Petrie 盘。"外科口罩和棉质口罩似乎都不能有效防止 SARS-CoV-2病毒的传播，这种病毒是由新型冠状病毒肺炎患者的咳嗽传播到环境和口罩表面的。"
*Singapore Study–Few people used mask correctly
*新加坡研究ー很少有人正确使用口罩
https://www.medpagetoday.com/infectiousdisease/publichealth/86601
Overall,data were collected from 714 men and women.About half the sample were women and all adult ages were represented.Only 90 participants(12.6%,95%CI 10.3%-15.3%)passed the visual mask fit test.About three-quarters performed strap placement incorrectly,61%left a"visible gap between the mask and skin,"and about 60%didn't tighten the nose-clip.
总的来说，数据收集自714名男性和女性。大约一半的样本是女性，所有的成年年龄都有代表。只有90名参与者(12.6%，95%置信区间10.3%-15.3%)通过了视觉面具匹配测试。大约四分之三的人没有正确地放置皮带，61%的人"在面具和皮肤之间留下了可见的缝隙"，大约60%的人没有收紧鼻夹。
*A 2011 randomized Australian clinical trial of standard medical/surgical masks
*2011年澳大利亚标准医用/外科口罩随机临床试验
Medical masks offered no protection at all from influenza.
医用口罩对流感一点保护作用都没有。
Conclusions from Organizations
各组织的结论
The World Health Organization(WHO):
世界卫生组织:
"Advice to decision makers on the use of masks for healthy people in community settings
"就在社区环境中为健康人士使用口罩向决策者提供咨询
As described above,the wide use of masks by healthy people in the community setting is not supported by current evidence and carries uncertainties and critical risks."
正如上文所述，健康人士在社区环境中广泛使用口罩并没有现有证据支持，而且带有不确定性和关键风险。」
"Medical masks should be reserved for health care workers.The use of medical masks in the community may create a false sense of security,with neglect of other essential measures,such as hand hygiene practices and physical distancing,and may lead to touching the face under the masks and under the eyes,result in unnecessary costs,and take masks away from those in health care who need them most,especially when masks are in short supply."
"医用口罩应该留给医护人员。在社区使用医用口罩可能造成一种虚假的安全感，忽视其他基本措施，如手部卫生习惯和身体距离，并可能导致触摸口罩下面和眼睛下面的面部，造成不必要的费用，并夺走最需要口罩的医护人员的口罩，特别是在口罩供应不足的情况下
"Masks are effective only when used in combination with frequent hand-cleaning with alcohol-based hand rub or soap and water."
口罩只有在与经常用酒精搓手液或肥皂和水洗手相结合时才有效
WHO acknowledges that most people do not use masks properly.
世卫组织承认，大多数人没有正确使用口罩。
Dr.Nancy Messonnier,director of the Center for the National Center for Immunization and Respiratory Diseases:
南希梅森尼尔博士，国家免疫和呼吸系统疾病中心主任:
https://www.cdc.gov/media/releases/2020/t0131-2019-novel-coronavirus.html
"We don't routinely recommend the use of face masks by the public to prevent respiratory illness,"said on January 31."And we certainly are not recommending that at this time for this new virus."
"我们不建议公众经常使用口罩来预防呼吸道疾病，"1月31日表示。"我们当然不建议在这个时候对这种新病毒采取这种做法。"
The Centers for Disease Control and Prevention(CDC)
美国疾病控制与预防中心
https://www.cdc.gov/flu/professionals/infectioncontrol/maskguidance.htm
In March 5,2019 regarding the flu:"Masks are not usually recommended in non-healthcare settings;however,this guidance provides other strategies for limiting the spread of influenza viruses in the community:
2019年3月5日，关于流感:"在非医疗机构通常不建议使用口罩，但是，这份指南提供了其他策略来限制流感病毒在社区的传播:
cover their nose and mouth when coughing or sneezing,
咳嗽或打喷嚏时，应掩盖口鼻,
use tissues to contain respiratory secretions and,after use,to dispose of them in the nearest waste receptacle,and
用纸巾包住呼吸道分泌物，并在使用后将其丢弃在最近的废物容器中，以及
perform hand hygiene(e.g.,handwashing with non-antimicrobial soap and water,and alcohol-based hand rub if soap and water are not available)after having contact with respiratory secretions and contaminated objects/materials.
接触呼吸道分泌物和受污染的物件/物料后，应注意手部衞生(例如用没有抗菌剂的肥皂和清水洗手，以及在没有肥皂和清水的情况下用酒精搓手)
From the New England Journal of Medicine
摘自《新英格兰医学杂志》
https://www.nejm.org/doi/full/10.1056/NEJMp2006372
"We know that wearing a mask outside health care facilities offers little,if any,protection from infection.Public health authorities define a significant exposure to Covid-19 as face-to-face contact within 6 feet with a patient with symptomatic Covid-19 that is sustained for at least a few minutes(and some say more than 10 minutes or even 30 minutes).The chance of catching Covid-19 from a passing interaction in a public space is therefore minimal.In many cases,the desire for widespread masking is a reflexive reaction to anxiety over the pandemic."
"我们知道，在医疗机构外面戴口罩对于防止感染几乎没有任何保护作用。公共卫生当局定义与有症状的新型冠状病毒肺炎患者在6英尺内的面对面接触，持续至少几分钟(有些人说超过10分钟甚至30分钟)。因此，在公共空间里，通过一个经过的互动来捕捉新型冠状病毒肺炎的机会是很小的。在许多情况下，渴望广泛的掩饰是对大流行的焦虑的反射性反应。"
Final Thoughts
最后的想法
Surgical masks–loose fitting.They are designed to protect the patient from the doctors'respiratory droplets.The wearer is not protected from others airborne particles
医用口罩.宽松配件。它们的设计是为了保护病人免受医生的呼吸道飞沫的伤害。佩戴者不受其他空气传播粒子的保护
People do not wear masks properly.Most people have the mask under the nose.The wearer does not have glasses on and the eyes are a portal of entry.
人们不会适当地戴口罩。大多数人都把口罩戴在鼻子底下。佩戴者不戴眼镜，眼睛是入口
The designer masks and scarves offer minimal protection–they give a false sense of security to both the wearer and those around the wearer.
设计师的面具和围巾提供了最低限度的保护——它们给穿戴者和周围的人一种虚假的安全感
**Not to mention they add a perverse lightheartedness to the situation.
**更不用说他们给这种情况增加了一种反常的轻松
If you are walking alone,no mask–avoid folks–that is common sense.
如果你独自行走，不要戴面具——避开人群——这是常识
Remember–children under 2 should not wear masks–accidental suffocation and difficulty breathing in some
记住-2岁以下的儿童不应该戴口罩-意外的窒息和呼吸困难
If wearing a mask makes people go out and get Vitamin D–go for it.In the 1918 flu pandemic people who went outside did better.Early reports are showing people with COVID-19 with low Vitamin D do worse than those with normal levels.Perhaps that is why shut-ins do so poorly.
如果戴口罩会让人们出去摄取维生素D，那就去吧。在1918年流感大流行，走出家门的人表现更好。早期报告显示，维生素D含量低的新型冠状病毒肺炎患者比维生素D含量正常的人情况更糟糕。也许这就是为什么自闭症患者表现如此糟糕的原因
https://www.medrxiv.org/content/10.1101/2020.04.08.20058578v4
If you are sick,stay home!
如果你生病了，就呆在家里！
Additional Resource:Healthy People Wearing Masks,Should They or Shouldn't They?This ER nurse with over two decades of experience took a deep dive into the science to find out:https://jennifermargulis.net/healthy-people-wearing-masks-during-covid19/
附加资源:健康人戴口罩，他们应该还是不应该？这位有着超过20年经验的急诊室护士深入研究科学，找到了答案:https://jennifermargulis.net/healthy-people-wearing-masks-during-covid19/
