Physical interventions to interrupt or reduce the spread of respiratory viruses

 

Abstract

Background

Viral epidemics or pandemics of acute respiratory infections like influenza or severe acute respiratory syndrome pose a global threat. Antiviral drugs and vaccinations may be insufficient to prevent their spread.

Objectives

To review the effectiveness of physical interventions to interrupt or reduce the spread of respiratory viruses.

Search methods

We searched The Cochrane Library, the Cochrane Central Register of Controlled Trials (CENTRAL 2010, Issue 3), which includes the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to October 2010), OLDMEDLINE (1950 to 1965), EMBASE (1990 to October 2010), CINAHL (1982 to October 2010), LILACS (2008 to October 2010), Indian MEDLARS (2008 to October 2010) and IMSEAR (2008 to October 2010).

Selection criteria

In this update, two review authors independently applied the inclusion criteria to all identified and retrieved articles and extracted data. We scanned 3775 titles, excluded 3560 and retrieved full papers of 215 studies, to include 66 papers of 67 studies. We included physical interventions (screening at entry ports, isolation, quarantine, social distancing, barriers, personal protection, hand hygiene) to prevent respiratory virus transmission. We included randomised controlled trials (RCTs), cohorts, case-controls, before-after and time series studies.

Data collection and analysis

We used a standardised form to assess trial eligibility. We assessed RCTs by randomisation method, allocation generation, concealment, blinding and follow up. We assessed non-RCTs for potential confounders and classified them as low, medium and high risk of bias.

Main results

We included 67 studies including randomised controlled trials and observational studies with a mixed risk of bias. A total number of participants is not included as the total would be made up of a heterogenous set of observations (participant people, observations on participants and countries (object of some studies)). The risk of bias for five RCTs and most cluster-RCTs was high. Observational studies were of mixed quality. Only case-control data were sufficiently homogeneous to allow meta-analysis. The highest quality cluster-RCTs suggest respiratory virus spread can be prevented by hygienic measures, such as handwashing, especially around younger children. Benefit from reduced transmission from children to household members is broadly supported also in other study designs where the potential for confounding is greater. Nine case-control studies suggested implementing transmission barriers, isolation and hygienic measures are effective at containing respiratory virus epidemics. Surgical masks or N95 respirators were the most consistent and comprehensive supportive measures. N95 respirators were non-inferior to simple surgical masks but more expensive, uncomfortable and irritating to skin. Adding virucidals or antiseptics to normal handwashing to decrease respiratory disease transmission remains uncertain. Global measures, such as screening at entry ports, led to a non-significant marginal delay in spread. There was limited evidence that social distancing was effective, especially if related to the risk of exposure.

Authors' conclusions

Simple and low-cost interventions would be useful for reducing transmission of epidemic respiratory viruses. Routine long-term implementation of some measures assessed might be difficult without the threat of an epidemic.

 

Plain language summary

Physical interventions to interrupt or reduce the spread of respiratory viruses

Although respiratory viruses usually only cause minor disease, they can cause epidemics. Approximately 10% to 15% of people worldwide contract influenza annually, with attack rates as high as 50% during major epidemics. Global pandemic viral infections have been devastating. In 2003 the severe acute respiratory syndrome (SARS) epidemic affected around 8000 people, killed 780 and caused an enormous social and economic crisis. In 2006 a new avian H5N1, and in 2009 a new H1N1 'swine' influenza pandemic threat, caused global anxiety. Single and potentially expensive measures (particularly the use of vaccines or antiviral drugs) may be insufficient to interrupt the spread. Therefore, we searched for evidence for the effectiveness of simple physical barriers (such as handwashing or wearing masks) in reducing the spread of respiratory viruses, including influenza viruses.

We included 67 studies including randomised controlled trials and observational studies with a mixed risk of bias. A total number of participants is not included as the total would be made up of a varied set of observations: participant people and observations on participants and countries (the object of some studies). Any total figure would therefore be misleading. Respiratory virus spread can be reduced by hygienic measures (such as handwashing), especially around younger children. Frequent handwashing can also reduce transmission from children to other household members. Implementing barriers to transmission, such as isolation, and hygienic measures (wearing masks, gloves and gowns) can be effective in containing respiratory virus epidemics or in hospital wards. We found no evidence that the more expensive, irritating and uncomfortable N95 respirators were superior to simple surgical masks. It is unclear if adding virucidals or antiseptics to normal handwashing with soap is more effective. There is insufficient evidence to support screening at entry ports and social distancing (spatial separation of at least one metre between those infected and those non-infected) as a method to reduce spread during epidemics.

 

摘要

背景

以物理性介入阻擾或減少呼吸道病毒的傳播

病毒的小流行或大流行均對人類產生重大威脅，諸如流行性感冒病毒、急性呼吸窘迫症候群等。抗病毒藥物及疫苗可能尚不足以預防像這樣重大的事件。

目標

系統性的回顧各種被用來阻止或是減少呼吸道病毒傳播的物理性介入方式的效用。

搜尋策略

我們搜尋Cochrane Central Register of Controlled Trials (CENTRAL) (考科藍圖書館2009年第2期); MEDLINE (1966年 −2009年5月); OLDMEDLINE (1950年 −1965年); EMBASE (1990年 −2009年5月); CINAHL (1982年 −2009年5月).

選擇標準

我們從2958個標題中排除了 2790 篇文獻，留下168個試驗，包括來自59個研究的41篇論文。我們納入了所有以物理性介入(隔離、檢疫、保持距離的社交活動、屏障、 個人防護、衛生設備)預防呼吸道病毒的傳染。我們納入了下述研究設計：隨機對照試驗、世代研究、個案對照、交叉研究、前後對照研究以及時間序列研究。

資料收集與分析

我們用標準化的格式評估試驗合格性。依據隨機分配的方式、世代分配、隱匿、單盲或雙盲、及追蹤的狀況來評估隨機對照試驗的品質。我們另外根據是否存在可能的干擾因素來評估非隨機對照的試驗，將之依偏差的程度分為低、中、高三等。

主要結論

4個RCTs還有多數叢集RCTs具有高度偏誤風險，觀察性研究的品質參差不齊。只有個案對照研究的數據具有同質性可以進行統合分析。最高品質的叢集RCTs認為可以透過公共衛生的方式， 預防呼吸道病毒傳播，譬如說洗手，特別是對於兒童來說。在其他的研究設計當中，可以清楚的看到對於降低從兒童到其他家庭成員傳染的額外好處，但後者可能存在的干擾因素較多。6個個案對照研究支持使用傳染屏障、隔離，以及改善個人衛生將有效牽制呼吸道病毒的流行。我們只找到有限的證據顯示N95口罩優於一般外科用簡單的口罩，而且它還比較貴，也比較不舒服，並且造成皮膚發炎。而在一般的洗手乳中添加消毒劑及抑菌劑所增加的效果依舊不明。全球化的方式，如入境篩檢、並沒被妥善的評估。僅有限的證據(特別是如果與暴露的風險有關)顯示擴大社交距離有效。

作者結論

許多簡單且低成本的介入方式可能對於呼吸道病毒流行時的傳播有預防的效果。但要評估某些文中所提及的預防方式，在長期使用上是否有效，在沒有大流行威脅時，可能並不容易。

翻譯人

本摘要由臺灣大學附設醫院簡郁珊翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

以物理性介入阻擾或減少呼吸道病毒的傳播：雖然呼吸道病毒感染通常只會造成輕微的疾病，但仍可能發生大流行。全世界每年大約有10% −15%的人會感染到流行性感冒，在大流行時此比例更可高達50%。因為期廣泛的傳播全球性的大流行已造成重大的傷害。如在2003年爆發的嚴重急性呼吸窘迫症候群的流行，影響了約8000個病人，其中780人死亡，造成巨大的社會經濟危機。 2006年 一種新的禽流感H5N1，以及於2009年一種新的H1N1 ’豬‘流感的威脅引起了極大的焦慮。簡單的方式 (特別是疫苗或是抗病毒藥物)可能不足以阻止傳播。因此，我們搜尋物理屏礙(像是洗手還是戴口罩)降低呼吸道病毒傳播的有效性，其中也包含了流行性感冒病毒。可以透過改善個人衛生降低呼吸道病毒傳播，(比如說洗手)，特別是對於年幼的小孩而言。 經常洗手也有助於減少兒童傳染給家庭成員。 使用傳染的障礙，譬如說隔離、以及公共衛生方式 (戴口罩、手套、袍子)可以有效控制院內呼吸道病毒流行。較貴、容易引起發炎而且又不舒服的N95也許優於一般簡單的口罩。在一般的洗手過程中加入消滅病毒或抗菌的成份是否能進一步減少呼吸道感染則仍不清楚。沒有充分證據支持入境篩檢以及擴大社交具離可以在流行時減少傳播。