en-us	Modes of transmission of virus causing COVID-19: implications for IPC precaution recommendations
zh-cn	导致COVID-19的病毒传播模式：对感染预防和控制方面的预防建议的影响

en-us	Scientific brief
zh-cn	科学简报

en-us	29 March 2020
zh-cn	2020年3月29日

en-us	Modes of transmission of the COVID-19 virus
zh-cn	COVID-19病毒的传播模式

en-us	Respiratory infections can be transmitted through droplets of different sizes: when the droplet particles are >5-10 μm in diameter they are referred to as respiratory droplets, and when then are <5μm in diameter, they are referred to as droplet nuclei.
zh-cn	呼吸道感染可以通过不同大小的飞沫传播：当飞沫颗粒的直径大于5-10微米时，它们被称为呼吸道飞沫，当直径小于5微米时，它们被称为飞沫核。

en-us	According to current evidence, COVID-19 virus is primarily transmitted between people through respiratory droplets and contact routes.
zh-cn	根据目前的证据，COVID-19病毒主要通过呼吸道飞沫和接触途径在人与人之间传播2-7。

en-us	2-7 In an analysis of 75,465 COVID-19 cases in China, airborne transmission was not reported. 
zh-cn	在对中国75465例COVID-19病例的分析中，没有关于空气传播的报告。

en-us	Droplet transmission occurs when a person is in in close contact (within 1 m) with someone who has respiratory symptoms (e.g., coughing or sneezing) and is therefore at risk of having his/her mucosae (mouth and nose) or conjunctiva (eyes) exposed to potentially infective respiratory droplets. 
zh-cn	当一个人与有呼吸道症状（如咳嗽或打喷嚏）的人密切接触（1米以内），因此其粘膜（嘴和鼻子）或结膜（眼睛）有暴露于潜在传染性呼吸道飞沫的风险时，就会发生飞沫传播。

en-us	Transmission may also occur through fomites in the immediate environment around the infected person.
zh-cn	传播也可能通过被感染者周围直接环境中的污染物发生。

en-us	Therefore, transmission of the COVID-19 virus can occur by direct contact with infected people and indirect contact with surfaces in the immediate environment or with objects used on the infected person (e.g., stethoscope or thermometer).  
zh-cn	因此，COVID-19病毒的传播有可能通过直接接触被感染者和间接接触直接环境中的表面或在被感染者身上使用过的物品（如听诊器或温度计）发生。

en-us	Airborne transmission is different from droplet transmission as it refers to the presence of microbes within droplet nuclei, which are generally considered to be particles <5μm in diameter, can remain in the air for long periods of time and be transmitted to others over distances greater than 1 m. 
zh-cn	空气传播不同于飞沫传播，空气传播指的是飞沫核内存在微生物，这些微生物通常被认为是直径小于5微米的颗粒，可在空气中停留很长一段时间，并跨越1米以上的距离传播给其他人。

en-us	In the context of COVID-19, airborne transmission may be possible in specific circumstances and settings in which procedures or support treatments that generate aerosols are performed; i.e., endotracheal intubation, bronchoscopy, open suctioning, administration of nebulized treatment, manual ventilation before intubation, turning the patient to the prone position, disconnecting the patient from the ventilator, non-invasive positive-pressure ventilation, tracheostomy, and cardiopulmonary resuscitation. 
zh-cn	就COVID-19而言，在实施产生气溶胶的程序或支持性治疗（即气管插管、支气管镜检查、开放式抽吸、雾化治疗、插管前手动通气、将患者转向俯卧位、将患者与呼吸机断开、无创正压通气、气管造口术和心肺复苏）的特定情况下和环境中，空气传播有可能发生。

en-us	There is some evidence that COVID-19 infection may lead to intestinal infection and be present in faeces. 
zh-cn	有证据表明COVID-19感染有可能导致肠道感染并出现在粪便中。

en-us	However, to date only one study has cultured the COVID-19 virus from a single stool specimen.  
zh-cn	然而，迄今为止，只有一项研究从一个粪便样本中培养出了COVID-19病毒。

en-us	There have been no reports of faecal−oral transmission of the COVID-19 virus to date. 
zh-cn	迄今为止还没有关于COVID-19病毒经粪-口传播的报告。

en-us	Implications of recent findings of detection of COVID-19 virus from air sampling 
zh-cn	空气采样检测COVID-19病毒的最新发现的含义

en-us	To date, some scientific publications provide initial evidence on whether the COVID-19 virus can be detected in the air and thus, some news outlets have suggested that there has been airborne transmission. 
zh-cn	迄今为止，一些科学出版物提供了关于COVID-19病毒是否能在空气中被检测到的初步证据，因此一些新闻媒体暗示存在空气传播。

en-us	These initial findings need to be interpreted carefully. 
zh-cn	需要审慎解读这些初步发现。

en-us	A recent publication in the New England Journal of Medicine has evaluated virus persistence of the COVID-19 virus. 
zh-cn	《新英格兰医学杂志》最近发表的一篇文章评估了COVID-19病毒的持久性。

en-us	In this experimental study, aerosols were generated using a three-jet Collison nebulizer and fed into a Goldberg drum under controlled laboratory conditions. 
zh-cn	在这项实验性研究中，使用三喷嘴科利森喷雾器产生气溶胶，并在受控的实验室条件下将其送入戈德堡鼓。

en-us	This is a high-powered machine that does not reflect normal human cough conditions. 
zh-cn	这是一台大功率机器，不能反映正常的人类咳嗽情况。

en-us	Further, the finding of COVID-19 virus in aerosol particles up to 3 hours does not reflect a clinical setting in which aerosol-generating procedures are performed—
zh-cn	此外，在存在时间长达3小时的气溶胶微粒中发现COVID-19病毒并不反映执行产生气溶胶的程序的临床环境，

en-us	that is, this was an experimentally induced aerosol-generating procedure.   
zh-cn	也就是说，这是一种实验诱导的气溶胶产生程序。

en-us	There are reports from settings where symptomatic COVID-19 patients have been admitted and in which no COVID-19 RNA was detected in air samples. 
zh-cn	有报告称，有症状的COVID-19患者已入院，但在空气样本中未检测到COVID-19核糖核酸。

en-us	WHO is aware of other studies which have evaluated the presence of COVID-19 RNA in air samples, but which are not yet published in peer-reviewed journals. 
zh-cn	世卫组织知道其它一些研究评估了空气样本中COVID-19核糖核酸的存在，但这些研究尚未在同行评审期刊上发表。

en-us	It is important to note that the detection of RNA in environmental samples based on PCR-based assays is not indicative of viable virus that could be transmissible. 
zh-cn	值得注意的是，基于聚合酶链反应检测的环境样本中核糖核酸的发现并不表明存在可传播的活病毒。

en-us	Further studies are needed to determine whether it is possible to detect COVID-19 virus in air samples from patient rooms where no procedures or support treatments that generate aerosols are ongoing. 
zh-cn	需要进一步的研究来确定是否有可能从并非正在实施产生气溶胶的程序或支持性治疗的病房的空气样本中检测到COVID-19病毒。

en-us	As evidence emerges, it is important to know whether viable virus is found and what role it may play in transmission.  
zh-cn	随着证据的出现，重要的是要知道是否发现了活病毒，以及它在传播中可能扮演的角色。

en-us	Conclusions
zh-cn	结论

en-us	Based on the available evidence, including the recent publications mentioned above, WHO continues to recommend droplet and contact precautions for those people caring for COVID-19 patients. 
zh-cn	根据现有证据，包括上述最近的出版物，世卫组织继续为护理COVID-19患者的人员推荐飞沫和接触预防措施。

en-us	WHO continues to recommend airborne precautions for circumstances and settings in which aerosol generating procedures and support treatment are performed, according to risk assessment. 
zh-cn	根据风险评估，世卫组织继续为实施产生气溶胶的程序和支持性治疗的情况和环境推荐空气传播预防措施。

en-us	These recommendations are consistent with other national and international guidelines, including those developed by the European Society of Intensive Care Medicine and Society of Critical Care Medicine14 and those currently used in Australia, Canada, and United Kingdom. 
zh-cn	这些建议与其它国家和国际指南一致，包括欧洲重症护理医学学会和重症护理医学学会制定的指南14以及澳大利亚、加拿大和联合王国目前使用的指南。

en-us	At the same time, other countries and organizations, including the US Centers for Diseases Control and Prevention and the European Centre for Disease Prevention and Control, recommend airborne precautions for any situation involving the care of COVID-19 patients, and consider the use of medical masks as an acceptable option in case of shortages of respirators (N95, FFP2 or FFP3). 
zh-cn	与此同时，其它一些国家和组织，包括美国疾病控制和预防中心和欧洲疾病预防和控制中心，建议对任何涉及COVID-19患者护理的情况采取空气传播预防措施，并考虑在防护口罩（N95、FFP2或FFP3）短缺的情况下使用医用口罩作为可接受的选择。

en-us	Current WHO recommendations emphasize the importance of rational and appropriate use of all PPE, not only masks, which requires correct and rigorous behavior from health care workers, particularly in doffing procedures and hand hygiene practices. 
zh-cn	世卫组织目前的建议强调合理和适当使用所有个人防护装备而不仅仅是口罩的重要性，这要求卫生保健工作者采取正确和严谨的行为，特别是在摘脱程序和手卫生做法方面。

en-us	WHO also recommends staff training on these recommendations,22 as well as the adequate procurement and availability of the necessary PPE and other supplies and facilities. 
zh-cn	世卫组织还建议对工作人员进行关于这些建议的培训22，以及适当采购和提供必要的个人防护装备和其他用品和设备。

en-us	Finally, WHO continues to emphasize the utmost importance of frequent hand hygiene, respiratory etiquette, and environmental cleaning and disinfection, as well as the importance of maintaining physical distances and avoidance of close, unprotected contact with people with fever or respiratory symptoms.  
zh-cn	最后，世卫组织继续强调时常注意手卫生、呼吸礼仪、环境清洁和消毒的极端重要性，以及保持身体距离和避免与有发热或呼吸道症状的人的近距离无保护接触的重要性。

en-us	WHO carefully monitors emerging evidence about this critical topic and will update this scientific brief as more information becomes available. 
zh-cn	世卫组织仔细监测关于这一关键主题的新证据，将在获得更多信息时更新这一科学简报。

en-us	WHO continues to monitor the situation closely for any changes that may affect this interim guidance. 
zh-cn	世卫组织继续密切监测可能影响本科学简报的任何变化。

en-us	Should any factors change, WHO will issue a further update. 
zh-cn	如果任何因素发生变化，世卫组织将发布进一步的更新。

en-us	Otherwise, this scientific brief will expire 2 years after the date of publication. 
zh-cn	否则，本科学简报将在发布日期2年后失效。

en-us	© World Health Organization 2020. 
zh-cn	世界卫生组织，2020年。

en-us	Some rights reserved. 
zh-cn	保留部分版权。

en-us	WHO carefully monitors emerging evidence about this critical topic and will update this scientific brief as more information becomes available. 
zh-cn	世卫组织仔细监测关于这一关键主题的新证据，将在获得更多信息时更新这一科学简报。