LETTER TO THE EDITOR 99 www.journals.viamedica.pl Address for correspondence: Francesco Chirico, Post-graduate School of Occupational Health, Università Cattolica del Sacro Cuore, Roma, Italy; e-mail: medlavchirico@gmail.com DOI: 10.5603/ARM.a2021.0028 Received: 22.01.2021 Copyright © 2021 PTChP ISSN 2451–4934 Francesco Chirico 1 , Gabriella Nucera 2 , Angelo Sacco 1 , Nicola Magnavita 1 1 Post-graduate School of Occupational Health, Università Cattolica del Sacro Cuore, Roma, Italy 2 ASST Fatebenefratelli and Sacco, Fatebenefratelli Hospital, Department of Emergency, Corso di Porta Nuova, Milano, Italy Proper respirators use is crucial for protecting both emergency frst aid responder and casualty from COVID‑19 and airborne-transmitted infections To the Editor We read with great interest the paper by Barycka et al. [1] in which the authors argue that healthcare workers (HCWs) should use fltering facepiece masks (FFP) with exhaust valve, when performing procedures such as cardiopulmonary resuscitation (CRP), to reduce the adverse effects of using FFP without valve, including high dis- comfort, low performance and thermal stress. Their letter, however, addresses numerous prevention problems and deserves some clar- ification. The literature agrees on the greater effectiveness of flter masks compared to surgical ones in protecting HCWs against microorganisms; however, it is known that flter masks do not offer absolute safety against coronaviruses and prevention must be based on the simultaneous adoption of many measures [2]. There is also a broad consensus that wearing a mask for the entire work shift during a pandemic can cause numerous symptoms in workers [3]. These problems, whose pathogenesis is due to a combination of ergonomic and psychosocial factors, require a careful choice of this Personal Protective Equipment (PPE), with the partici- patory contribution of workers, as indicated by the European Directives on health and safety at workplace. However, we believe that the example cho- sen by the authors to illustrate their claim is not appropriate. Cardiopulmonary resuscitation (CPR) is not an exclusively hospital procedure, because it must be performed in prehospital setting, including when needed at workplace. In addition, no HCW carries out this activity for the entire work shift. Consequently, extrapolating the conditions of the long-time occupational mask user to the rescuer doing CPR in the workplace can be misleading. During frst aid, indeed, rescuer and casualty come into close contact, especially during CRP. Mouth-to-mouth resuscitation poses, therefore, the greatest risk of COVID-19 infection not only to rescuer, but also to the casualty. For this reason, ERC guidelines suggest that appropriate PPEs, such as gloves, masks and visor eye protection should we worn by rescuers, whereas the casu- alty should wear surgical mask. FFP masks, fur- thermore, must be made of flter material, cover the nose and mouth, and possibly also the chin (semi-mask) [4]. It is possible, indeed, that lay or medical frst aid responders who are asymptomatic carriers can transmit the SARS-CoV-2 virus to casualty, if they use respirators with EV [5]. It is well known that HCWs are at high risk of infection and can be a source of infection [6, 7]. Asymptomatic or presymptomatic HCWs acting as potential “superspreaders” were cited as responsible of COVID-19 hospital outbreaks [8]. At the same time, casualty can be particularly “vulnerable” to COVID-19 infection [8]. SARS-CoV-2 is a highly contagious virus and facial respirators could be insuffcient to prevent the infection, because the “minimal infective dose” of the virus responsible for COVID-19 in- fection is unknown [4, 9]. Therefore, adverse