Modelling the impact of the mandatory use of face coverings
on public transport and in retail outlets in the UK on COVID-19-related
infections, hospital admissions and
mortality
Adrian H Heald1,2, Michael Stedman3,
Zixing Tian2, Pensee Wu4, Anthony A
Fryer4
1Department of Diabetes and Endocrinology, Salford
Royal NHS Foundation Trust, Salford, UK.
2The School of Medicine and Manchester Academic Health
Sciences Centre, The University of Manchester, Manchester, UK.
3Res Consortium, Andover, UK.
4School of Medicine, Keele University, Keele,
Staffordshire, UK
Short title : Impact of face coverings on COVID-19 spread
Acknowledgements : None
Correspondence : Professor Tony Fryer, Professor of Clinical
Biochemistry, School of Medicine, Keele University, Keele,
Staffordshire, UK. Email:
a.a.fryer@keele.ac.uk
ABSTRACT
Introduction
The rapid spread of the pandemic caused by the severe acute respiratory
syndrome coronavirus 2 (SARS-CoV-2/)(COVID-19) virus resulted in
governments around the world instigating a range of measures, including
mandating the wearing of face coverings on public transport/in retail
outlets.
Methods
We developed a sequential assessment of the risk reduction provided by
face coverings using a step-by-step approach. The United Kingdom Office
of National Statistics (ONS) Population Survey data was utilised to
determine the baseline total number of community-derived infections.
These were linked to reported hospital admissions/hospital deaths to
create case admission risk ratio and admission-related fatality rate. We
evaluated published evidence to establish an infection risk reduction
for face coverings. We calculated an Infection Risk Score (IRS) for a
number of common activities and related it to the effectiveness of
reducing infection and its consequences, with a face covering, and
evaluated their effect when applied to different infection rates over 3
months from 24th July 2020, when face coverings were
made compulsory in England on public transport/retail outlets.
Results
We show that only 7.3% of all community-based infection risk is
associated with public transport/retail outlets. In the week of
24th July, The reported weekly community infection
rate was 29,400 new cases at the start (24th July). The rate of growth
in hospital admissions and deaths for England was around -15%/week,
suggesting the infection rate, R, in the most vulnerable populations was
just above 0.8. In this situation, average infections over the evaluated
13 week follow-up period, was 9,517/week with face covering of 40%
effectiveness, this reduced average infections by 844/week, hospital
admissions by 8/week and deaths by 0.6/week; a fall of 9% over the
period total. If, however, the R-value rises to 1.0, then average
community infections would have stayed at 29,400/week and mandatory face
coverings could reduce average weekly infections by 3,930, hospital
admissions by 36 and deaths by 2.9/week; a 13% reduction.
These reductions should be seen in the context that there was an average
of 102,000/week all-cause hospital emergency admissions in England in
June and 8,900 total reported deaths in the week ending 7th August 2020.
Conclusion
We have illustrated that the policy on mandatory use of face coverings
in retail outlets/on public transport may have been very well followed,
but may be of limited value in reducing hospital admissions and deaths,
at least at the time that it was introduced, unless infections begin to
rise faster than currently seen. The impact appears small compared to
all other sources of risk, thereby raising questions regarding the
effectiveness of the policy.