NIH对一次性口罩
有最新研究，希望
去污后还能保持有效防护
本文摘译自NIAID官网2020年4月15日新闻稿，以下为详文：
据美国国立卫生研究院（National Institutes of Health）的科学家称，N95防护口罩可以被有效去污且保持功能完整，最多有三种方法。N95防护口罩是专为一次性使用而设计的，医护人员佩戴它是为了减少暴露在空气中的传染源，包括引起COVID-19的病毒。这项研究是在一个受控实验室环境中进行的，结果已公布在今日预印服务器上。研究结果尚未经过同行评审，但正在共享，以协助公共卫生部门应对COVID-19。
NIH原文截图
这项研究的调查人员是蒙大拿州（Montana）汉密尔顿（Hamilton）的美国国立卫生研究院（National Institutes of Health）洛基山实验室（RML）的成员，该实验室隶属于美国国家过敏和传染病研究所（NIAID）。他们与来自加州大学洛杉矶分校的合作者一起，测试了N95滤布小段的去污效果，这些滤布曾接触过导致COVID-19的SARS-CoV-2病毒。测试的去污方法包括汽化过氧化氢（VHP）、70摄氏度干热、紫外线和70％乙醇喷雾。
所有四种方法均从N95织物测试样品中消除了可检测到的活病毒。研究人员随后用同样的去污方法处理了完好无损的、干净的防护口罩，以测试其重复使用的耐久性。为确定防护口罩在面部是否保持适当的贴合度和密封性，RML员工志愿者佩戴口罩两个小时；使用相同的程序对每个口罩重复进行了三次去污。
科学家们发现，在两次去污之后，乙醇喷雾剂会破坏防护口罩的贴合度和密封性，因此不推荐将乙醇喷雾剂用于N95防护口罩的消毒。经紫外线和热处理的三次消毒后，防护口罩开始出现贴合性和密封性问题——表明这些防护口罩可以重复使用两次。经VHP处理的口罩没有出现故障，表明它们有潜在可能地被重复使用三次。
作者认为，VHP是最有效的去污方法，因为仅经过10分钟的处理就无法检测到病毒。只要紫外线和干热方法应用至少60分钟，是可以被接受的去污程序。作者敦促，任何将N95防护口罩去污的人，在每次重复使用之前，需要检查防护口罩在面部的贴合度和密封性。
（备注：预印本是未经同行评审认证工作的初步报告。不应依靠它们来指导临床实践或与健康相关的行为，也不应在新闻媒体中将其作为既定信息进行报道。）
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
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 The findings are not yet peer-reviewed but are being shared to assist the public health response to COVID-19.
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.
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.
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.
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.
