Abstract：
BACKGROUND: Tight-fitting masks and respirators, in manikin studies, improved aerosol source control compared to loose-fitting masks. Whether this translates to humans is not known.
METHODS: We compared efficacy of masks (cloth and surgical) and respirators (KN95 and N95) as source control for SARS-CoV-2 viral load in exhaled breath of volunteers with COVID-19 using a controlled human experimental study. Volunteers (N = 44, 43% female) provided paired unmasked and masked breath samples allowing computation of source-control factors.
RESULTS: All masks and respirators significantly reduced exhaled viral load, without fit tests or training. A duckbill N95 reduced exhaled viral load by 98% (95% CI: 97%-99%), and significantly outperformed a KN95 (p < 0.001) as well as cloth and surgical masks. Cloth masks outperformed a surgical mask (p = 0.027) and the tested KN95 (p = 0.014).
CONCLUSIONS: These results suggest that N95 respirators could be the standard of care in nursing homes and healthcare settings when respiratory viral infections are prevalent in the community and healthcare-associated transmission risk is elevated.
BACKGROUND: Defense Advanced Research Projects Agency, National Institute of Allergy and Infectious Diseases, Centers for Disease Control and Prevention, the Bill & Melinda Gates Foundation, and The Flu Lab.
METHODS: We compared efficacy of masks (cloth and surgical) and respirators (KN95 and N95) as source control for SARS-CoV-2 viral load in exhaled breath of volunteers with COVID-19 using a controlled human experimental study. Volunteers (N = 44, 43% female) provided paired unmasked and masked breath samples allowing computation of source-control factors.
RESULTS: All masks and respirators significantly reduced exhaled viral load, without fit tests or training. A duckbill N95 reduced exhaled viral load by 98% (95% CI: 97%-99%), and significantly outperformed a KN95 (p < 0.001) as well as cloth and surgical masks. Cloth masks outperformed a surgical mask (p = 0.027) and the tested KN95 (p = 0.014).
CONCLUSIONS: These results suggest that N95 respirators could be the standard of care in nursing homes and healthcare settings when respiratory viral infections are prevalent in the community and healthcare-associated transmission risk is elevated.
BACKGROUND: Defense Advanced Research Projects Agency, National Institute of Allergy and Infectious Diseases, Centers for Disease Control and Prevention, the Bill & Melinda Gates Foundation, and The Flu Lab.
摘要：
背景：紧密贴合的口罩和呼吸器，在人体模型研究中，与宽松的口罩相比，改进了气溶胶源控制。这是否转化为人类尚不清楚。
方法：我们比较了口罩（布和手术）和呼吸器（KN95和N95）作为COVID-19志愿者呼出气中SARS-CoV-2病毒载量的来源对照的有效性。志愿者（N=44，女性占43％）提供了成对的未掩盖和掩盖的呼吸样本，从而可以计算源控制因子。
结果：所有的口罩和呼吸器都显著降低了呼出的病毒载量，没有合适的测试或培训。鸭嘴N95使呼出的病毒载量减少了98％（95％CI：97％-99％），并且显著优于KN95(p<0.001)以及布和外科口罩。布面罩优于外科面罩(p=0.027)和测试的KN95(p=0.014)。
结论：这些结果表明，当呼吸道病毒感染在社区中普遍存在且与医疗保健相关的传播风险升高时，N95呼吸器可能成为疗养院和医疗机构的护理标准。
背景：国防高级研究计划局，国家过敏和传染病研究所，疾病控制和预防中心,比尔和梅林达·盖茨基金会,还有流感实验室.
方法：我们比较了口罩（布和手术）和呼吸器（KN95和N95）作为COVID-19志愿者呼出气中SARS-CoV-2病毒载量的来源对照的有效性。志愿者（N=44，女性占43％）提供了成对的未掩盖和掩盖的呼吸样本，从而可以计算源控制因子。
结果：所有的口罩和呼吸器都显著降低了呼出的病毒载量，没有合适的测试或培训。鸭嘴N95使呼出的病毒载量减少了98％（95％CI：97％-99％），并且显著优于KN95(p<0.001)以及布和外科口罩。布面罩优于外科面罩(p=0.027)和测试的KN95(p=0.014)。
结论：这些结果表明，当呼吸道病毒感染在社区中普遍存在且与医疗保健相关的传播风险升高时，N95呼吸器可能成为疗养院和医疗机构的护理标准。
背景：国防高级研究计划局，国家过敏和传染病研究所，疾病控制和预防中心,比尔和梅林达·盖茨基金会,还有流感实验室.
