by World Health Organization · 2019 · Cited by 125 — pdf, accessed 26 June 2019). 120 Zhang Q, Wang D. Antiviral prophylaxis and isolation for the control of pandemic influenza. Int J Environ Res Public Health

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iiISBN 978-92-4-151683-9 © World Health Organization 2019 Some rights reserved. This work is available under the Creative Commons Attribution- NonCommercial-ShareAlike 3.0 IGO licence (CC BY-NC-SA 3.0 IGO; licenses/by-nc-sa/3.0/igo ). Under the terms of this licence, you may copy, redistribute and adapt the work for non-commercial purposes, provided the work is appropriately cited, as indicated below. In any use of this work, there should be no suggestion that WHO endorses any speci˜c organization, products or services. The use of the WHO logo is not permitted. If you adapt the work, then you must license your work under the same or equivalent Creative Commons licence. If you create a translation of this work, you should add the following disclaimer along with the suggested citation: fiThis translation was not created by the World Health Organization (WHO). WHO is not responsible for the content or accuracy of this translation. The original English edition shall be the binding and authentic editionfl. Any mediation relating to disputes arising under the licence shall be conducted in accordance with the mediation rules of the World Intellectual Property Organization. Suggested citation. Non-pharmaceutical public health measures for mitigating the risk and impact of epidemic and pandemic in˚uenza; 2019. Licence: CC BY-NC-SA 3.0 IGO .Cataloguing-in-Publication (CIP) data. CIP data are available at Sales, rights and licensing. To purchase WHO publications, see To submit requests for commercial use and queries on rights and licensing, see about/licensing. Third-party materials. If you wish to reuse material from this work that is attributed to a third party, such as tables, ˜gures or images, it is your responsibility to determine whether permission is needed for that reuse and to obtain permission from the copyright holder. The risk of claims resulting from infringement of any third-party-owned component in the work rests solely with the user. General disclaimers. The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of WHO concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted and dashed lines on maps represent approximate border lines for which there may not yet be full agreement. The mention of speci˜c companies or of certain manufacturers™ products does not imply that they are endorsed or recommended by WHO in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters. All reasonable precautions have been taken by WHO to verify the information contained in this publication. However, the published material is being distributed without warranty of any kind, either expressed or implied. The responsibility for the interpretation and use of the material lies with the reader. In no event shall WHO be liable for damages arising from its use. ii

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iiiWORLD HEALTH ORGANIZATION Acknowledgements ivAbbreviations and acronyms vGlossary viExecutive summary 11. Introduction 5 1.1. Introduction 5 1.1.1. Human in˜uenza virus transmission 5 1.1.2. Public health importance 5 1.1.3. History of the guidelines for NPIs in in˜uenza pandemics 9 1.2. Scope, purpose and target audience 9 1.3. International Health Regulations 10 1.4. Pandemic in˜uenza severity assessment framework 10 1.5. Guideline development process 10 1.5.1. Contributors to the process 10 1.5.2. Guideline development steps 112. Summary of recommendations 133. Communication for behavioural impact 194. Personal protective measures 20 4.1. Hand hygiene 20 4.2. Respiratory etiquette 24 4.3. Face masks 265. Environmental measures 28 5.1. Surface and object cleaning 28 5.2. Other environmental measures 31 5.2.1. Ultraviolet light 31 5.2.2. Increased ventilation 33 5.2.3. Modifying humidity 356. Social distancing measures 37 6.1. Contact tracing 37 6.2. Isolation of sick individuals 40 6.3. Quarantine of exposed individuals 44 6.4. School measures and closures 48 6.5. Workplace measures and closures 53 6.6. Avoiding crowding 577. Travel-related measures 79 7.1. Travel advice 60 7.2. Entry and exit screening 62 7.3. Internal travel restrictions 64 7.4. Border closure 67References 70Contents Non-pharmaceutical public health measures for mitigating the risk and impact of epidemic and pandemic in˜uenza

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NON-PHARMACEUTICAL PUBLIC HEALTH MEASURES FOR MITIGATING THE RISK AND IMPACT OF EPIDEMIC AND PANDEMIC INFLUENZA ivAcknowledgements This document is the product of collaboration between the World Health Organization (WHO) Global In˜uenza Programme and the WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, The University of Hong Kong. The University of Hong Kong team was led by Benjamin Cowling, and included Jessica Wong, Sukhyun Ryu, Huizhi Gao, Eunice Shiu, Jingyi Xiao and Min Whui Fong. The team™s contributions to carrying out the systematic reviews and developing this document are gratefully acknowledged. WHO appreciates the contributions of the following experts before, during and after the Technical Consultation on Non-pharmaceutical Public Health Measures for Mitigating the Risk and Impact of Epidemic and Pandemic In˜uenza, which was held from 26 to 28 March 2019 in Hong Kong Special Administrative Region (SAR), China: Allison Aiello, Alanoud Aljifri, Gemma Arellano, Gina Charos, Francisco de Paula Júnior, Aleksander Deptu˚a, Narangerel Dorj, Hind Ezzine, Rosaura Gutiérrez-Vargas, Anand Krishnan, Vernon Lee, Svenn-Erik Mamelund, Punam Mangtani, Je˛rey McFarland, Armelle Viviane Ngomba, Jonathan Nguyen Van-Tam, Hitoshi Oshitani, Pasi Penttinen, Carrie Reed, Amra Uzicanin and Dayan Wang. WHO also wishes to extend its appreciation to all who reviewed and commented on the earlier version of this document during the public comment period. The following individuals identi˝ed themselves but are not among the lists above: Faruque Ahmed, Salah Al Awaidy, Kossi Badziklou, Aleksander Deptula, Luzhao Feng, Gary Lamont, Raina Nikiforova, Junxiong Vincent Pang, Trinehessevik Paulsen and Osvaldo Uez. The following WHO sta˛ and consultants are acknowledged for their contributions to the development and review of this document: Abdinasir Abubakar, Isabelle Bergeri, Sylvie Briand, Caroline S. Brown, Amgad A. Elkholy, Julia Fitzner, Philip Gould, Aspen Hammond, Michala Hegermann-Lindencrone, Belinda L. Herring, Masaya Kato, Jaya Lamichhane, Ann Moen, Sonja Olsen, Soatiana C. Rajatonirina, Gina Samaan, Magdi Samaan, Bhagawan D. Shrestha, Katelijn A.H. Vandemaele, Andrea Vicari, Wenqing Zhang and Weigong Zhou. The technical editing of this document was performed by Hilary Cadman and the Cadman Editing Services team.

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vWORLD HEALTH ORGANIZATION Abbreviations and acronyms ACH air changes per hourCI con˝dence interval COMBI communication for behavioural impact GDP gross domestic product GRADE Grading of Recommendations Assessment, Development and Evaluation IHR International Health Regulations NPI non-pharmaceutical intervention OR odds ratio PISA pandemic in˜uenza severity assessment RCT randomized controlled trial RNA ribonucleic acid RR rate ratio SAR Special Administrative Region USA United States of America UV ultraviolet WHO World Health Organization

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NON-PHARMACEUTICAL PUBLIC HEALTH MEASURES FOR MITIGATING THE RISK AND IMPACT OF EPIDEMIC AND PANDEMIC INFLUENZA viGlossary Contact tracing Identi˝cation and follow-up of persons who may have come into contact with an infected person. Closure Halting the operation of an institution or business. Entry and exit screening Screening travellers for in˜uenza virus infection at their arrival in and departure from border crossings, ports and airports. Isolation Separation or con˝nement of a person who has or is suspected of having in˜uenza virus infection, to prevent further infections. Movement restriction Limitation on the movements of a person who has or is suspected of having in˜uenza virus infection. Personal protective measures Measures to reduce personal risk of infection, such as hand washing and face masks. Quarantine Separation or restriction of the movement of persons who may be infected, based either on exposure to other infected people or on a history of travel to a˛ected areas. R0 Basic reproductive number, a measure of transmissibility. This number represents the average number of people infected by one infectious case in a completely susceptible population. Respiratory etiquette Simple hygiene practices taken by people who are coughing or sneezing to prevent person-to-person transmission of respiratory infections. Symptomatic in˜uenza In˜uenza virus infection causing an acute illness, most commonly with rapid onset of fever and other respiratory symptoms, although a proportion of illnesses are afebrile. Travel Advice Health advice to travellers provided by national or international health agencies to help travellers understand the risks involved during the travel and take the necessary preventive measures or precautions to protect their health while travelling.

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NON-PHARMACEUTICAL PUBLIC HEALTH MEASURES FOR MITIGATING THE RISK AND IMPACT OF EPIDEMIC AND PANDEMIC INFLUENZA 2Available evidence The evidence base for this guideline included systematic reviews of 18 NPIs, covering: Ł personal protective measures (e.g. hand hygiene, respiratory etiquette and face masks); Ł environmental measures (e.g. surface and object cleaning, and other environmental measures); Ł social distancing measures (e.g. contact tracing, isolation of sick individuals, quarantine of exposed individuals, school measures and closures, workplace measures and closures, and avoiding crowding); and Ł travel-related measures (e.g. travel advice, entry and exit screening, internal travel restrictions and border closure). The evidence base on the e˛ectiveness of NPIs in community settings is limited, and the overall quality of evidence was very low for most interventions. There have been a number of high- quality randomized controlled trials (RCTs) demonstrating that personal protective measures such as hand hygiene and face masks have, at best, a small e˛ect on in˜uenza transmission, although higher compliance in a severe pandemic might improve e˛ectiveness. However, there are few RCTs for other NPIs, and much of the evidence base is from observational studies and computer simulations. School closures can reduce in˜uenza transmission but would need to be carefully timed in order to achieve mitigation objectives. Travel-related measures are unlikely to be successful in most locations because current screening tools such as thermal scanners cannot identify pre-symptomatic infections and afebrile infections, and travel restrictions and travel bans are likely to have prohibitive economic consequences. Recommendations Eighteen recommendations are provided in this guideline (Table 1). The recommendations take into account the quality of the supporting evidence, the strength of each recommendation and other considerations. In taking decisions on interventions, each WHO Member State and each local area will need to take into account the feasibility and acceptability of proposed interventions, in addition to their anticipated e˛ectiveness and impact. This guideline provides an overview of relevant considerations.

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3WORLD HEALTH ORGANIZATION Any Moderate HighExtraordinary Not recommended in any circumstances Hand hygiene Respiratory etiquette Face masks for symptomatic individuals Surface and object cleaning Increased ventilation Isolation of sick individuals Travel advice As above, plus Avoiding crowding As above, plus Face masks for public School measures and closures As above, plus Workplace measures and closures Internal travel restrictions UV light Modifying humidity Contact tracing Quarantine of exposed individuals Entry and exit screening Border closure Hand hygiene Respiratory etiquette Face masks for symptomatic individualsSurface and object cleaning Increased ventilation Isolation of sick individuals Travel advice As above, plus Avoiding crowding As above, plus Face masks for public School measures and closures As above, plus Workplace measures and closures UV light Modifying humidity Contact tracing Quarantine of exposed individualsEntry and exit screening Internal travel restrictions Border closure SEVERITY PANDEMIC a EPIDEMIC Table 1. Recommendations on the use of NPIs by severity level NPI: non-pharmaceutical intervention; UV: ultraviolet. a A pandemic is de˜ned as a global epidemic caused by a new in˚uenza virus to which there is little or no pre-existing immunity in the human population ( 1).

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NON-PHARMACEUTICAL PUBLIC HEALTH MEASURES FOR MITIGATING THE RISK AND IMPACT OF EPIDEMIC AND PANDEMIC INFLUENZA 4The most e˛ective strategy to mitigate the impact of a pandemic is to reduce contacts between infected and uninfected persons, thereby reducing the spread of infection, the peak demand for hospital beds, and the total number of infections, hospitalizations and deaths. However, social distancing measures (e.g. contact tracing, isolation, quarantine, school and workplace measures and closures, and avoiding crowding) can be highly disruptive, and the cost of these measures must be weighed against their potential impact. Early assessments of the severity and likely impact of the pandemic strain will help public health authorities to determine the strength of intervention. In all in˜uenza epidemics and pandemics, recommending that those who are ill isolate themselves at home should reduce transmission. Facilitating this should be a particular priority. In more severe pandemics, measures to increase social distancing in schools, workplaces and public areas would further reduce transmission. Experimental studies suggest that hand hygiene can reduce virus on the hands. However, there is insu˙cient scienti˝c evidence from RCTs to support the e˙cacy of hand hygiene alone to reduce in˜uenza transmission in in˜uenza epidemics and pandemics. Hand hygiene is an important intervention to reduce the risk of other common infectious diseases; therefore, it should be recommended at all times , regardless of the lack of e˙cacy against con˝rmed in˜uenza reported in a number of RCTs. There is also a lack of evidence for the e˛ectiveness of improved respiratory etiquette and the use of face masks in community settings during in˜uenza epidemics and pandemics. Nevertheless, these NPIs may be conditionally recommended for ill persons because of other considerations (e.g. the high cost of face masks), and they are generally feasible and acceptable. It is likely that these personal interventions could be e˛ective if implemented in combination. There is su˙cient evidence on the lack of e˛ectiveness of entry and exit screening to justify not recommending these measures in in˜uenza pandemics and epidemics. There is weak evidence, mainly from simulation studies, that travel restrictions may only delay the introduction of infections for a short period, and this measure may a˛ect mitigation programmes, be disruptive of supply chains or be unacceptable to communities for various reasons. There is no evidence on the e˛ectiveness of travel advice; however, given the potential bene˝ts. it is recommended that health authorities provide advice for travellers. Border closures may be considered only by small island nations in severe pandemics and epidemics, but must be weighed against potentially serious economic consequences. This document will serve as a core component of WHO™s in˜uenza prevention and control programme in community settings. The successful implementation of this guideline depends on the inclusion of NPIs as a robust strategic plan at national and local levels, as well as the appropriate application of its recommendations.

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5WORLD HEALTH ORGANIZATION Introduction1.1. Introduction 1.1.1. Human in˜uenza virus transmission In˜uenza virus infection causes acute respiratory illness that is usually self-limiting but can be severe in some cases. In˜uenza virus infects the upper and lower respiratory tract, and spreads between people, mainly during close contact. The routes of transmission are often categorized into three speci˝c modes Œ contact, aerosols and (large) respiratory droplets ( 2) Œ as outlined below. Contact transmission Contact transmission is either direct or indirect. Transmission via direct physical contact can occur between an infected individual and a susceptible individual (e.g. through kissing or shaking hands). Transmission via indirect contact occurs through an intermediate object (e.g. touching contaminated surfaces or objects, and then touching nose or eyes) (2). Several studies have shown that in˜uenza virus can survive for prolonged periods on certain types of surfaces, and can survive on hands for a short time ( 3).Aerosol transmission In˜uenza virus can be detected in ˝ne particle aerosols with an aerodynamic diameter of less than 5 ˆm, emitted by infected individuals in exhalations, coughs and sneezes ( 4). These tiny particles (<5 ˆm) can reach the membrane surfaces of the upper respiratory tract and the epithelial cells of the lower respiratory tract ( 2). Although most aerosol transmission is likely to occur at close range because of dilution and inactivation over distance and time, these particles can remain suspended in the air for extended periods and may be responsible for higher rates of transmission, particularly in crowded areas ( 5).Respiratory droplet transmission Droplet transmission is typically de˝ned as transmission via droplets that follow a ballistic trajectory after emission and do not remain airborne; these particles have an aerodynamic diameter of 5Œ10 ˆm ( 6). Virus-laden droplets are expelled into the environment by breathing, coughing and sneezing. These droplets generally travel short distances (1Œ2 m from the source) ( 5). Respiratory droplets are often thought to be the most common route of in˜uenza transmission, although there is limited evidence to support this view. Impacts of modes of transmission The various modes of transmission have implications for the e˛ectiveness of personal protective measures against in˜uenza transmission. Also, uncertainty over the speci˝c role of contact and aerosol transmission has hindered the optimization of control strategies. In settings where multiple exposures occur, removing one mode of transmission (e.g. by intense hand hygiene) may not be su˙cient to reduce overall transmission ( 7). Isolating infected individuals Œ that is, keeping them away from others Œ is likely to reduce transmission by all modes. 1.1.2. Public health importance In˜uenza epidemics cause considerable impact each year, and in˜uenza pandemics occur from time to time with potentially devastating health and economic e˛ects. Because of the delay in the availability of speci˝c vaccines and the limited stockpiles of antiviral drugs, non-pharmaceutical interventions (NPIs) are often the only available intervention when a new pandemic in˜uenza virus emerges and begins to spread ( 8). The implementation of community mitigation measures may help to reduce the impact of in˜uenza epidemics and pandemics. 1. 106 KB – 91 Pages