Department of Family Medicine, University of Colorado School of Medicine, Aurora, Colorado.
Ann Fam Med. 2021 Jan-Feb;19(1):55-62. doi: 10.1370/afm.2640.
The coronavirus disease 2019 (COVID-19) pandemic has led at times to a scarcity of personal protective equipment, including medical masks, for health care clinicians, especially in primary care settings. The objective of this review was to summarize current evidence regarding the use of cloth masks to prevent respiratory viral infections, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), among health care clinicians.
We searched 5 databases, the Centers for Disease Control and Prevention website, and the reference lists of identified articles on April 3, 2020. All identified publications were independently screened by 2 reviewers. Two authors independently extracted data and graded the studies. Randomized control trials (RCTs) were graded using the Consolidated Standards of Reporting Trials (CONSORT) checklist, and observational and nonhuman subject studies were graded using 11 domains common across frequently used critical appraisal tools. All discrepancies were resolved by consensus.
Our search identified 136 original publications. Nine studies met inclusion criteria. We performed a qualitative synthesis of the data from these studies. Four nonrandomized trials, 3 laboratory studies, 1 single-case experiment, and 1 RCT were identified. The laboratory studies found that cloth materials provided measurable levels of particle filtration but were less efficacious at blocking biologic material than medical masks. The RCT found that cloth masks were associated with significantly more viral infections than medical masks.
The current literature suggests that cloth materials are somewhat efficacious in filtering particulate matter and aerosols but provide a worse fit and inferior protection compared to medical masks in clinical environments. The quality and quantity of literature addressing this question are lacking. Cloth masks lack evidence for adequate protection of health care clinicians against respiratory viral infections.
2019 年冠状病毒病（COVID-19）大流行有时导致包括医用口罩在内的个人防护设备短缺，尤其是在初级保健环境中。本综述的目的是总结目前关于使用布制口罩预防医护人员呼吸道病毒感染（如严重急性呼吸综合征冠状病毒 2（SARS-CoV-2））的证据。
我们于 2020 年 4 月 3 日在 5 个数据库、疾病控制与预防中心网站以及已确定文章的参考文献中进行了检索。由 2 位评审员独立筛选所有确定的出版物。两位作者独立提取数据并对研究进行分级。使用 CONSORT 清单对随机对照试验（RCT）进行分级，使用常用于常用批判性评估工具的 11 个领域对观察性和非人类研究进行分级。所有分歧均通过共识解决。
我们的搜索确定了 136 篇原始出版物。有 9 项研究符合纳入标准。我们对这些研究的数据进行了定性综合。确定了 4 项非随机试验、3 项实验室研究、1 项单病例实验和 1 项 RCT。实验室研究发现，布制材料可提供可测量水平的颗粒过滤，但在阻挡生物材料方面的效果不如医用口罩。RCT 发现，布口罩与医用口罩相比，与病毒感染的相关性显著更高。
目前的文献表明，布制材料在过滤颗粒物和气溶胶方面有一定效果，但在临床环境中与医用口罩相比，其贴合度和保护效果较差。解决这个问题的文献的质量和数量都不足。布口罩缺乏足够保护医护人员免受呼吸道病毒感染的证据。
