Introduction
The international coronavirus disease (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has resulted in governments around the world instigating a range of measures to limit spread and facilitate economical recovery. One of these measures, adopted by several countries, includes the use of face coverings in enclosed spaces were social distancing is not possible.
In the United Kingdom (UK), after initially suggesting that face coverings were not necessary, the UK government introduced mandatory use of face coverings on public transport on the 15th June 2020, and in retail outlets on the 24th July 2020.1 This was aimed at offsetting some of the additional infection risks being taken by reduced social distancing from 2 metres to ‘1 metre plus’, thereby facilitating easing of restrictions and supporting plans to stimulate the economy, particularly in the hard-hit retail sector. One of the drivers to the implementation of this policy was the review published by the Royal Society of Medicine and the British Academy which stated that ‘cloth face coverings are effective in reducing source virus transmission, i.e., outward protection of others, when they are of optimal material and construction (high-grade cotton, hybrid and multilayer) and fitted correctly and for source protection of the wearer’ 2
UK government guidance at the time stated that; ‘The best available scientific evidence is that, when used correctly, wearing a face-covering may reduce the spread of coronavirus droplets in certain circumstances, helping to protect others’. 1 This statement is undoubtedly true. However, the real-world impact of the use of face-covering on public transport and in retail outlets in the UK has received little attention. At the time of writing this article, there are no data to assess this objectively.
While data is emerging from other countries on the impact of precautionary measures, including the use of face coverings, these address the issue from a range of perspectives. For example, Hseih et al attempted to estimate the impact by examining the co-incidence of mass mask use and influenza infections.3 However, it is difficult to determine whether the take-up of face coverings wearing was responsible for the observed changes. Chu et al performed a systematic review and meta-analysis of 172 observational studies across 16 countries and six continents, on three precautionary measures, including the use of face coverings .4 They suggested that face masks have value in reducing the spread of infection. However, in the assessment of face masks, the majority of studies were in healthcare settings; only three (n=725; examining the SARS virus in China and Vietnam) were from non-healthcare settings, where wearing face masks was associated with a lower risk of infection (relative risk 0·56, 95% CI 0·40 to 0·79). The American College of Physicians also raises questions around the evidence to support the effectiveness of face coverings in reducing transmission.5
While there is a debate about the effectiveness of face coverings in terms of the spread of infections, there is also an argument that such analysis should also assess the wider consequences, including economic and mental health-associated effects. To our knowledge, there is no published data on the economic impact of the use of face coverings in the UK, though Goldman Sachs estimated that introducing national mandatory use of face coverings could potentially prevent additional restrictions that would otherwise cost around 5% of US GDP.6 Furthermore a recent short review by Tian et al7 found that, in relation to face coverings, the evidence indicates that a higher-level specification of face masks are essential to protect health care workers from COVID-19 infection and that community face coverings in the case of well individuals could be beneficial in certain circumstances, where transmission may be pre-symptomatic.
In terms of mental health, while it may be argued that, irrespective of the actual effectiveness, the mandating of use of face coverings in enclosed spaces provides a measure of reassurance to the wearer, there are potentially wider mental health implications which make a thorough assessment critical, particularly at a time when mental well-being is being stretched to the limits.8,9,10 Wearing of face coverings may provide a degree of short-term reassurance to people with some types of mental health challenge,11 whilst others may perceive the increased use of face coverings as heightening their sense of threat and insecurity.12
Given the potential physical, social, economic and mental implications of implementing this policy, we sought to model its potential impact. Using available data, we examined the number of infections, hospital admissions and hospital deaths potentially prevented by the use of face coverings in retail outlets and on public transport.