NIH對一次性口罩
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去污后還能保持有效防護

本文摘譯自NIAID官網2020年4月15日新聞稿，以下為詳文：

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據美國國立衛生研究院（National Institutes of Health）的科學家稱，N95防護口罩可以被有效去污且保持功能完整，最多有三種方法。N95防護口罩是專為一次性使用而設計的，醫護人員佩戴它是為了減少暴露在空氣中的傳染源，包括引起COVID-19的病毒。這項研究是在一個受控實驗室環境中進行的，結果已公布在今日預印服務器上。研究結果尚未經過同行評審，但正在共享，以協助公共衛生部門應對COVID-19。?

NIH原文截圖

這項研究的調查人員是蒙大拿州（Montana）漢密爾頓（Hamilton）的美國國立衛生研究院（National Institutes of Health）洛基山實驗室（RML）的成員，該實驗室隸屬于美國國家過敏和傳染病研究所（NIAID）。他們與來自加州大學洛杉磯分校的合作者一起，測試了N95濾布小段的去污效果，這些濾布曾接觸過導致COVID-19的SARS-CoV-2病毒。測試的去污方法包括汽化過氧化氫（VHP）、70攝氏度干熱、紫外線和70％乙醇噴霧。

所有四種方法均從N95織物測試樣品中消除了可檢測到的活病毒。研究人員隨后用同樣的去污方法處理了完好無損的、干凈的防護口罩，以測試其重復使用的耐久性。為確定防護口罩在面部是否保持適當的貼合度和密封性，RML員工志愿者佩戴口罩兩個小時；使用相同的程序對每個口罩重復進行了三次去污。?

科學家們發現，在兩次去污之后，乙醇噴霧劑會破壞防護口罩的貼合度和密封性，因此不推薦將乙醇噴霧劑用于N95防護口罩的消毒。經紫外線和熱處理的三次消毒后，防護口罩開始出現貼合性和密封性問題——表明這些防護口罩可以重復使用兩次。經VHP處理的口罩沒有出現故障，表明它們有潛在可能地被重復使用三次。

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作者認為，VHP是最有效的去污方法，因為僅經過10分鐘的處理就無法檢測到病毒。只要紫外線和干熱方法應用至少60分鐘，是可以被接受的去污程序。作者敦促，任何將N95防護口罩去污的人，在每次重復使用之前，需要檢查防護口罩在面部的貼合度和密封性。

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（備注：預印本是未經同行評審認證工作的初步報告。不應依靠它們來指導臨床實踐或與健康相關的行為，也不應在新聞媒體中將其作為既定信息進行報道。）?

原文：

NIH Study Validates Decontamination Methods For Re-Use of N95 Respirators

Three Methods Effectively Sanitized Masks for Limited Re-Use

April 15, 2020

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N95 respirators can be decontaminated effectively and maintain functional integrity for up to three uses, according to National Institutes of Health scientists. N95 respirators are designed for single-use and are worn by healthcare providers to reduce exposure to airborne infectious agents, including the virus that causes COVID-19.? The study was conducted in a controlled laboratory setting, and the results were posted on a preprint server on today. The findings are not yet peer-reviewed but are being shared to assist the public health response to COVID-19.?

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The study investigators are with NIH’s Rocky Mountain Laboratories (RML) in Hamilton, Montana, part of the National Institute of Allergy and Infectious Diseases (NIAID). With collaborators from the University of California, Los Angeles, they tested the decontamination of small sections of N95 filter fabric that had been exposed to SARS-CoV-2, the virus that causes COVID-19.? Decontamination methods tested included vaporized hydrogen peroxide (VHP), 70-degree Celsius dry heat, ultraviolet light, and 70% ethanol spray.

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All four methods eliminated detectable viable virus from the N95 fabric test samples. The investigators then treated fully intact, clean respirators with the same decontamination methods to test their reuse durability. Volunteer RML employees wore the masks for two hours to determine if they maintained a proper fit and seal over the face; decontamination was repeated three times with each mask using the same procedure.

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The scientists found that ethanol spray damaged the integrity of the respirator’s fit and seal after two decontamination sessions and therefore do not recommend it for decontaminating N95 respirators.? UV and heat-treated respirators began showing fit and seal problems after three decontaminations—suggesting these respirators potentially could be re-used twice. The VHP-treated masks experienced no failures, suggesting they potentially could be re-used three times.

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The authors concluded that VHP was the most effective decontamination method, because no virus could be detected after only a 10-minute treatment. UV and dry heat were acceptable decontamination procedures as long as the methods are applied for at least 60 minutes. The authors urge anyone decontaminating an N95 respirator to check the fit and seal over the face before each re-use.

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