To determine the risk of SARS-CoV-2 transmission by aerosols, to provide evidence on the rational use of masks, and to discuss additional measures important for the protection of healthcare workers from COVID-19. Literature review and expert opinion. SARS-CoV-2, the pathogen causing COVID-19, is considered to be transmitted via droplets rather than aerosols, but droplets with strong directional airflow support may spread further than 2 m. High rates of COVID-19 infections in healthcare-workers (HCWs) have been reported from several countries. Respirators such as filtering face piece (FFP) 2 masks were designed to protect HCWs, while surgical masks were originally intended to protect patients (e.g., during surgery). Nevertheless, high quality standard surgical masks (type II/IIR according to European Norm EN 14683) appear to be as effective as FFP2 masks in preventing droplet-associated viral infections of HCWs as reported from influenza or SARS. So far, no head-to-head trials with these masks have been published for COVID-19. Neither mask type completely prevents transmission, which may be due to inappropriate handling and alternative transmission pathways. Therefore, compliance with a bundle of infection control measures including thorough hand hygiene is key. During high-risk procedures, both droplets and aerosols may be produced, reason why respirators are indicated for these interventions.

中文翻译：

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气溶胶传播 SARS-CoV-2 的风险、合理使用口罩以及保护医护人员免受 COVID-19 侵害。

确定通过气溶胶传播 SARS-CoV-2 的风险，提供合理使用口罩的证据，并讨论对保护医护人员免受 COVID-19 侵害的其他重要措施。文献综述和专家意见。SARS-CoV-2 是导致 COVID-19 的病原体，被认为是通过飞沫而不是气溶胶传播的，但具有强定向气流支持的飞沫可能传播超过 2 m。多个国家报告称，医护人员 (HCW) 的 COVID-19 感染率很高。诸如过滤面罩 (FFP) 2 面罩之类的呼吸器旨在保护医护人员，而外科口罩最初旨在保护患者（例如，在手术期间）。尽管如此，高质量的标准外科口罩（根据欧洲标准 EN 14683 的 II/IIR 型）似乎与 FFP2 口罩一样有效，可防止流感或 SARS 报告的医护人员飞沫相关病毒感染。到目前为止，还没有针对 COVID-19 使用这些口罩进行的头对头试验。两种面罩类型都不能完全阻止传播，这可能是由于处理不当和替代传播途径所致。因此，遵守包括彻底的手部卫生在内的一系列感染控制措施是关键。在高风险操作过程中，可能会产生飞沫和气溶胶，这就是为什么需要使用呼吸器进行这些干预的原因。两种面罩类型都不能完全阻止传播，这可能是由于处理不当和替代传播途径所致。因此，遵守包括彻底的手部卫生在内的一系列感染控制措施是关键。在高风险操作过程中，可能会产生飞沫和气溶胶，这就是为什么需要使用呼吸器进行这些干预的原因。两种面罩类型都不能完全阻止传播，这可能是由于处理不当和替代传播途径所致。因此，遵守包括彻底的手部卫生在内的一系列感染控制措施是关键。在高风险操作过程中，可能会产生飞沫和气溶胶，这就是为什么需要使用呼吸器进行这些干预的原因。