LAUSR

One of the emerging aspects of the current severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), coronavirus disease 2019 (COVID-19) pandemic, is how different governments and institutions interpret and apply the same scientific evidence. This impacts on how the local guidance within each country is written and passed down to health and care workers and the general public. Although a consensus amongst experts would be ideal, this is difficult if not impossible with a new emerging pathogen, and in some aspects, such as aerosol transmission, many experts already have pre-conceived notions which have been upheld for a long time related to other pathogens [1–3]. Such preconceptions and strongly held opinions will hamper any consensus, and bias how emerging evidence is interpreted for any new pathogen. Issues around how a new infectious agent spreads are perhaps the most predominant, as the interventions such as social distancing, lockdowns and use of personal protective equipment (PPE) can have direct and practical impact on how people live, work and study. One of the most dramatic instances of this was (and is) the ongoing advice over the wearing of face masks. Face masks have been used to some extent in Asia for many years to protect against inorganic airborne pollutants [4–6], so the extension to wearing masks to protect against airborne infection was relatively easy. The key aspect here is how quickly the universal masking was adopted in many Asian counties for this purpose – particularly those who had experienced and were hardest hit by the 2003 SARS-CoV-1 outbreaks. Such universal masking reduces cross-transmission and effectively creates a degree of herd immunity, which may explain why countries like Hong Kong, Taiwan, Vietnam, South Korea and Japan have experienced relatively few COVID-19 cases and deaths [7–12]. Thus, the impact of COVID-19 has been far less in those countries that experienced the SARS-CoV-12,003 or Middle East respiratory syndrome coronavirus (MERSCoV) outbreaks, whose populations were already used to wearing face masks. This is in stark contrast to the countries that have not had this experience (including UK, Europe, North and South America), where such masking culture was relatively absent and the casualties from COVID-19 have been much higher [7, 8]. Of course, the control of COVID-19 in those Asian countries was not just due to mask-wearing but this was achieved in combination with other factors such as a relatively compliant populations, and the efficient, rapid roll-outs of mass testing, tracking and tracing, with prompt isolation of those infected, or the quarantining of those exposed. Healthcare systems in many developed countries have gradually become more adapted to dealing with noncommunicable chronic diseases (e.g. diabetes, chronic heart and lung disease, rheumatological conditions, dementia and Parkinson’s disease, etc.), depending mostly on effective vaccination programmes and a good supply of antimicrobials to deal with infectious diseases. Thus, they may be ill-prepared to deal with novel emerging pathogens. Yet, in such situations, as in any other walk of life, where expertise lies elsewhere, it seems sensible to seek and heed such advice in this case, the Asian countries that had experienced the 2003 SARS-CoV-1 outbreaks, many of whom had also dealt with emerging threats from avian influenza A(H5N1), A(H7N9) and Middle East Respiratory Syndrome coronavirus (MERS) [13] . Governments and populations in these Asian countries readily accepted that masking in public would protect everyone to some extent, despite relatively little evidence for the benefit of masks available at that time [14–16]. There was no prolonged debate about this and it was