[Evidence summary:] What is the current evidence for the effectiveness of using a visor rather than a surgical face mask in preventing the transmission of COVID-19 in a healthcare setting? [v1.0]

The use of face masks is part of a comprehensive package of prevention and control measures that can limit the spread of certain respiratory viral diseases, including COVID-19. Masks can be used either for protection of healthy persons [worn to protect oneself when in contact with an infected individual] or for source control [worn by an infected individual to prevent onward transmission]. In the event of severe shortage of medical masks, face shields may be considered as an alternative in health facilities; however, the use of cloth masks as an alternative to medical masks is not considered appropriate for protection of health workers based on limited available evidence. When providing care for certain categories of patients, the wearing of masks can present practical difficulties. In such circumstances it is appropriate to perform an institutional risk assessment and to consider alternatives to mask use that adequately manage the risk of transmission. When aerosol-generating procedures (AGPs) are performed, FFP2 masks are required in addition to eye protection. If a valved, non-shrouded respirator mask is used, facial protection such as a visor must always be worn.1 When advising the general public, mask-wearing was originally discouraged on the grounds that limited stocks of personal protective equipment (PPE) at the time meant that health workers may not have been able to access face masks; however, with increased manufacture of PPE and the re-engineering of some supply chains, the widespread availability of masks has resulted in greater encouragement of mask-wearing. In some cases, masks are now required to access certain premises. In certain circumstances where individuals may experience difficulty in wearing a face mask, the HSE suggests using a full face visor or face shield. While a visor is not as effective as a face mask in terms of protection, it may be utilised as an alternative. However, you should still wear a face mask if you have or have been caring for someone with COVID-19, or are self-isolating and cannot maintain a 2 metre distance from others in your household.