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.