Sommerstein, RamiRamiSommerstein0000-0003-1011-6878Fux, Christoph AndreasChristoph AndreasFuxVuichard-Gysin, DanielleDanielleVuichard-GysinAbbas, MohamedMohamedAbbasMarschall, JonasJonasMarschall0000-0002-0052-3210Balmelli, CarloCarloBalmelliTroillet, NicolasNicolasTroilletHarbarth, StephanStephanHarbarthSchlegel, MatthiasMatthiasSchlegelWidmer, AndreasAndreasWidmer2024-09-022024-09-022020-07-06https://boris-portal.unibe.ch/handle/20.500.12422/36456OBJECTIVES 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. METHODS Literature review and expert opinion. SHORT CONCLUSION 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.enAerosol COVID-19 Droplet Infection control Mask SARS-CoV-2 Transmission600 - Technology::610 - Medicine & healtharticle10.7892/boris.1451403263145010.1186/s13756-020-00763-0