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International Journal of Nursing Studies 108 (2020) 103629

Contents lists available at ScienceDirect

International Journal of Nursing Studies

j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / i j n s

A rapid systematic review of the efficacy of face masks and respirators

against coronaviruses and other respiratory transmissible viruses for

the community, healthcare workers and sick patients

C. Raina MacIntyre a , Abrar Ahmad Chughtai b , ∗

a The Kirby Institute, UNSW Medicine, University of New South Wales, Sydney, Australia b School of Public Health and Community Medicine, UNSW Medicine, University of New South Wales, Room 228, Level 2 Samuels Building, Sydney, Australia

a r t i c l e i n f o

Article history:

Received 24 March 2020

Received in revised form 18 April 2020

Accepted 21 April 2020

Keywords:

Coronavirus

Coronavirus disease

COVID19

Mask

Respirators

Personal protective equipment

a b s t r a c t

Background: The pandemic of COVID-19 is growing, and a shortage of masks and respirators has been

reported globally. Policies of health organizations for healthcare workers are inconsistent, with a change

in policy in the US for universal face mask use. The aim of this study was to review the evidence around

the efficacy of masks and respirators for healthcare workers, sick patients and the general public.

Methods: A systematic review of randomized controlled clinical trials on use of respiratory protection by

healthcare workers, sick patients and community members was conducted. Articles were searched on

Medline and Embase using key search terms.

Results: A total of 19 randomised controlled trials were included in this study – 8 in community set-

tings, 6 in healthcare settings and 5 as source control. Most of these randomised controlled trials used

different interventions and outcome measures. In the community, masks appeared to be effective with

and without hand hygiene, and both together are more protective. Randomised controlled trials in health

care workers showed that respirators, if worn continually during a shift, were effective but not if worn

intermittently. Medical masks were not effective, and cloth masks even less effective. When used by sick

patients randomised controlled trials suggested protection of well contacts.

Conclusion: The study suggests that community mask use by well people could be beneficial, particularly

for COVID-19, where transmission may be pre-symptomatic. The studies of masks as source control also

suggest a benefit, and may be important during the COVID-19 pandemic in universal community face

mask use as well as in health care settings. Trials in healthcare workers support the use of respirators

continuously during a shift. This may prevent health worker infections and deaths from COVID-19, as

aerosolisation in the hospital setting has been documented.

© 2020 The Author(s). Published by Elsevier Ltd.

This is an open access article under the CC BY-NC-ND license.

( http://creativecommons.org/licenses/by-nc-nd/4.0/ )

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(

hat is already known about the topic?

• Masks and respirators are commonly used to protect from res- piratory infections in three different indications – for healthcare

workers, sick patients and well community members.

• Currently there is debate and conflicting guidelines around the use of masks and respirators in healthcare and community set-

tings.

∗ Corresponding author. E-mail addresses: [email protected] (C.R. MacIntyre),

[email protected] (A .A . Chughtai).

ttps://doi.org/10.1016/j.ijnurstu.2020.103629

020-7489/© 2020 The Author(s). Published by Elsevier Ltd. This is an open access article

http://creativecommons.org/licenses/by-nc-nd/4.0/ )

hat this paper adds

• In the community, masks may be more protective for well peo- ple.

• In healthcare settings continuous use of respirators, is more protective compared to the medical masks, and medical masks

are more protective than cloth masks. Depending on the fabric

and design, some cloth masks may not be safe for healthcare

workers.

• The use of masks by sick patients is likely protective, and coro- naviruses can be emitted in normal breathing, in fine airborne

particles.

under the CC BY-NC-ND license.

2 C.R. MacIntyre and A .A . Chughtai / International Journal of Nursing Studies 108 (2020) 103629

Fig. 1. Search strategy and selection of papers.

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1. Introduction

The use of personal protective equipment for coronavirus dis-

ease (COVID-19) has been controversial, with differing guidelines

issued by different agencies ( Chen et al., 2020 ). COVID-19 is caused

by severe acute respiratory syndrome coronavirus2 (SARS-CoV-2),

a beta-coronavirus, similar to severe acute respiratory syndrome

coronavirus (SARS CoV) ( Chen et al., 2020 ). Seasonal alpha and

beta coronaviruses cause common colds, croup and broncholitis.

The transmission mode of coronaviruses in humans is similar,

thought to be by droplet, contact and sometimes airborne routes

( Ong et al., 2020 ; Zhang et al., 2020 ; Zou et al., 2020 ). The World

Health Organization recommends surgical mask for health work-

ers providing routine care to a coronavirus disease patient ( World

Health Organisation (WHO) 2020 ), whilst the US Centers for Dis-

ease Control and Prevention recommended a respirator ( Center for

Disease Control and Prevention CDC, 2020 ). Most authorities, ex-

cept the US CDC, are recommending that community members not

wear a mask, and that a mask should only be worn by a sick pa-

tient (also referred to as source control ) ( Chughtai et al., 2020 ).

There are more randomised controlled trials of community use of

masks in well people than studies of the use by sick people ( source

control ). The aim of this study was to review the randomised con-

trolled trials evidence for use of masks and respirators by the com-

munity, health care workers and sick patients for prevention of in-

fection.

2. Methods

We searched Medline and EmBase for clinical trials on masks

and respirators using the key words “mask”, “respirator”, and “per-

sonal protective equipment”. The search was conducted between 1

March to April 17 2020, and all randomised controlled trials pub-

lished before the search date were included. Two authors (CRM

and AAC) reviewed the title and abstracts to identify randomised

controlled trials on masks and respirators. We also searched rel-

evant papers from the reference lists of previous clinical trials

and systematic reviews. Studies that were not randomised con-

trolled trials, were about anesthesia, or not about prevention of in-

fection were excluded. Animal studies, experimental and observa-

tional epidemiologic studies were also excluded. Studies published

in English language were included.

We found 602 papers on Medline and 250 on Embase. 820 pa-

pers were excluded by title and abstract review. Full texts were re-

viewed for 32 papers and 19 were selected in this review. Results

were reported according to the Preferred Reporting Items for Sys-

tematic Reviews and Meta-Analyses (PRISMA) criteria ( Moher et al.,

2015 ).

3. Results

In general, the results show protection for healthcare work-

ers and community members, and likely benefit of masks used as

source control. We found eight clinical trials ( Aiello et al., 2012 ;

Simmerman et al., 2011 ; Larson et al., 2010 ; Aiello et al., 2010 ;

MacIntyre et al., 2009 ; Cowling et al., 2008 , Suess et al., 2012 ;

Cowling et al., 2009 ) on the use of masks in the community

( Table 1 ). In the community, masks appear to be effective with

and without hand hygiene, and both together are more protec-

tive ( Aiello et al., 2012 ; Aiello et al., 2010 ; MacIntyre et al., 2009).

However, some randomised controlled trials which measured both

hand hygiene and masks measured the effect of hand hygiene

alone, but not of masks alone ( Simmerman et al., 2011 , Cowling

et al., 2009 ). In more than one trial, interventions had to be used

within 36 hours of exposure to be effective ( Cowling et al., 2009 ;

Suess et al., 2012 ).

To date, six randomised controlled trials ( Radonovich et al.,

019 ; Jacobs et al., 2009 , Loeb et al., 2009; MacIntyre et al., 2011,

013, 2015 ) have been conducted on the use of masks and/or res-

irators by healthcare workers in health care settings ( Table 2 ). The

ealthcare worker trials ( Table 2 ) used different interventions and

ifferent outcome measures, and one was in the outpatient set-

ing. A Japanese study had only 32 subjects, and likely was under-

owered to find any difference between masks and control ( Jacobs

t al., 2009 ). Two North American trials of masks and respirators

gainst influenza infection found no difference between the arms,

ut neither had a control arm to differentiate equal efficacy from

qual inefficacy ( Radonovich et al., 2019 , Loeb et al., 2009 ). Nei-

her trial can prove equivalence, as this requires one intervention

o be already proven efficaceous against placebo. Without a con-

rol group to determine rates of influenza in unprotected health-

are workers, neither study is able to determine efficacy if no dif-

erence was observed between the two interventions. A serologic

tudy showed that up to 23% of unprotected healthcare workers (a

ate identical to that observed in Loeb the trial, which also used

erology) contract influenza during outbreaks ( Elder et al., 1996 ),

hich suggests lack of efficacy. Studies of nosocomial influenza

enerally find lower influenza attack rates in unprotected health-

are workers than observed in the Loeb trial ( Salgado et al., 2002 ).

Further problems with this study are that the majority of sub-

ects were defined as having influenza on the basis of serological

ositivity ( Loeb et al., 2009 ). The 10% seroconversion to pandemic

1N109 (with no pandemic virus isolation or positive PCR) ob-

erved in the trial, suggests that pandemic H1N109 was circulating

n Ontario before April 2009, which is unlikely.

A serological definition of influenza can be affected by vaccina-

ion. The authors claim they excluded influenza vaccinated subjects

n the outcome, but according to figure 1 in the Loeb trial, ( Loeb

t al., 2009 ) these subjects (130 in total) are included in the anal-

sis. If they had been excluded and even if no other subjects were

xcluded, the total analysed would be 348, which is lower than

he 422 subjects analysed ( Loeb et al., 2009 ). These 130 vaccinated

ubjects should have been excluded entirely from the analysis. The

accination status of subjects with seropositivity is not provided

n the paper, but it appears people with positive serology due to

accination may have been misclassified as influenza cases ( Loeb

t al., 2009 ).

C.R. MacIntyre and A .A . Chughtai / International Journal of Nursing Studies 108 (2020) 103629 3

Table 1

Community mask trials.

Author, year N, country Interventions Results

Cowling et al. (2008) 198 Households

Hong Kong

Medical masks

Hand washing

Control

NS – this was a preliminary report of the 2009 trial.

MacIntyre et al. (2009) 143 Households

Australia

Medical masks

P2 masks

Control

Intention to treat non-significant. Adherence with mask

wearing low (25-30% by day 5). In sub-analysis,

masks/P2 protective if adherent.

Cowling et al., 2009 ) 407 households

Hong Kong

Hand hygiene

Masks + hand hygiene Control

Intention to treat not significant. Masks plus hand hygiene

protective against lab confirmed influenza if used within

36 hours. Hand hygiene alone not significant.

Aiello et al. (2010 ) 1437 college students, United

States of America

Masks Masks + hand washing

Control

Intention to treat non-significant. Masks + handwashing protective in week 4 -6 of observation and beyond.

Aiello et al. (2012 ) 1178 college students, United

States of America

Masks

Masks + hand hygiene Control

Intention to treat non-significant. Masks + hand hygiene protective in week 3 of observation and beyond. Masks

alone not protective.

Larson et al. (2010 ) 617 households, United States of

America

Health education (HE)

Hand hygiene + HE Masks + hand hygiene + HE

Masks + hand hygiene + HE protective against secondary transmission measured by confirmed influenza and ILI.

Mean secondary attack rates for HE, HE + HH, HE + HH + M groups were 0.023, 0.020, and 0.018, respectively

Simmerman et al. (2011 ) 465 index patients and their

families, Thailand

Hand hygiene

Masks + hand hygiene Control

No significant difference in confirmed influenza infection

Suess et al. (2012) 84 index cases and 218

household contacts, Germany

Masks

Masks + hand hygiene Control

Intention to treat analysis was non-significant. Where used

within 36 h, secondary infection in the pooled M and

MH groups was significantly lower compared to the

control group. In multivariable analysis for predictors of

qRT-PCR confirmed influenza infection and clinical

influenza among included households in separate models

allowing for within household correlation, M and MH

were protective against Influenza AH1N1pdm09.

Table 2

Trials of mask and respirator use by health care workers.

Author, year N healthcare workers, Country Interventions Results

Jacobs et al. (2009) 32

Japan

Medical masks

Control

NS

Loeb et al. (2009) 446

Canada

Medical masks, targeted N95 No significant difference between Masks and targeted

N95

MacIntyre et al. (2011) 1441

China

Masks

N95 respirators, fit tested

N95 respirators, non-fit tested

Control

Continuous N95 protective against clinical, viral and

bacterial endpoints

MacIntyre et al. (2013) 1669

China

Medical Mask

N95 (continuous)

N95 (targeted)

Continuous N95 protective

No difference between targeted N95 and medical

masks

MacIntyre et al. (2015) 1607

Vietnam

Medical masks, cloth masks,

control

Medical masks protective or Cloth masks increase risk of

infection

Radonovich et al. (2019 ) 2862

United States of America

Medical masks, targeted

N95 (when 2 m from

confirmed respiratory

infection) in Outpatient

setting.

No significant difference between

Masks and targeted N95

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In both the North American trials, the intervention comprised

earing the mask or respirator when in contact with recognized

LI or when doing a high risk procedure, which is a targeted strat-

gy ( Radonovich et al., 2019 , Loeb et al., 2009 ). One was in an

utpatient setting. ( Radonovich et al., 2019 ) We conducted a ran-

omised controlled trial comparing the targeted strategy tested in

he two North American studies, with the wearing of respiratory

rotection during an entire shift, and showed efficacy for contin-

al (but not targeted) use of a respirator ( MacIntyre et al., 2013 ).

he study also did not show efficacy for a surgical mask worn con-

inually, and therefore no difference between a surgical mask and

argeted use of a respirator ( MacIntyre et al., 2013 ), which is con-

istent with the findings of the North American trials ( Radonovich

t al., 2019 , Loeb et al., 2009 ). In summary, the evidence is con-

istent that a respirator must be worn throughout the shift to be

rotective. Targeted use of respirators only when doing high risk

rocedures and medical mask use is not protective. Another ran-

omised controlled trial we conducted in China showed efficacy

or continual use of a respirator, but not for a mask, and also found

t-testing of the respirator did not affect efficacy ( MacIntyre et al.,

011 ). However, this may be specific to the quality of the tested

roduct, and is not generalisable to other respirators – fit testing

s a necessary part of respirator use ( Chughtai et al., 2015 ).

For healthcare workers, there is evidence of efficacy of respi-

ators if worn continually during a shift, but no evidence of effi-

acy of a mask ( MacIntyre et al., 2011, 2013 ). For hospitals where

OVID-19 patients are being treated, there is growing evidence of

idespread contamination of the ward environment, well beyond

m from the patient, as well as aerosol transmission ( Ong et al.,

020 ; Santarpia et al., n.d. ; Guo et al., 2020 ). Several studies have

4 C.R. MacIntyre and A .A . Chughtai / International Journal of Nursing Studies 108 (2020) 103629

Table 3

Trials of Masks used by a sick patient as source control.

Author, year N , country Interventions Results

Johnson et al. (2009 ) 9 subjects with confirmed influenza,

Australia

Medical mask

N95 (participants coughed 5 times onto

a Petri dish wearing each device)

NS - Surgical and N95 masks were equally

effective in preventing the spread of

PCR-detectable influenza

Canini et al. (2010) 105 index cases and 306 household

contacts, France

Medical mask

Control

No significant difference, but trial

terminated early

MacIntyre et al. (2016) 245 index cases and 597 household

contacts,

Medical mask worn by sick case

Control (no mask) Household contacts

Followed for infection.

Intention to treat analysis not significant.

Mask protective if worn

Barasheed et al. (2014) Hajj Setting. 22 tents were randomised to

‘mask’ ( n = 12) or ‘control’ ( n = 10) 75 pilgrims in ‘mask’ and 89 in ‘control’

group

Saudi Arabia

Mask and control Less ILI among the contacts of mask users

compared to the control tents (31%

versus 53%, p = 0.04). Laboratory results did not show any

difference between the two groups

Leung et al. (2020 ) Experimental study of 246 subjects

randomised to surgical mask and no

mask

Mask and control 111 were infected by human (seasonal)

coronavirus. Coronavirus found in

exhaled breath of no-mask subjects but

not in mask wearers. More virus was

found in fine aerosols than large

droplets

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found SARS-CoV-2 on air vents and in air samples in intensive care

units and COVID-19 wards ( Santarpia et al., n.d. ; Chia et al., 2020 ;

Liu et al., 2020 ), and an experimental study showed the virus in

air samples three hours after aerosolization ( van Doremalen et al.,

2020 ). The weight of this evidence and the precautionary princi-

ple ( MacIntyre et al., 2014 a; 2014 b), favors respirators for health-

care workers. We showed lower rates of infection outcomes in the

medical mask arm compared to control, but the difference was not

significant ( MacIntyre et al., 2011 ). It could be that larger trials are

needed to demonstrate efficacy of a mask, but any protection is far

less than from a respirator. A trial we conducted in Vietnam of 2-

layered cotton cloth masks compared to medical masks showed a

lower rate of infection in the medical mask group, and a 13 times

higher risk of infection in the cloth mask arm ( MacIntyre et al.,

2015 ). The study suggests cloth masks may increase the risk of in-

fection ( MacIntyre et al., 2015 ), but may not be generalizable to

all homemade masks. The material, design and adequacy of wash-

ing of cloth masks may have been a factor ( Macintyre et al., 2020 ).

There are no other randomised controlled trial of cloth masks pub-

lished at this time, but if any protection is offered by these it

would be less than even a medical mask.

Table 3 shows the trials of source control. There were five ran-

domised controlled trials identified of masks used by sick patients

( Johnson et al., 2009 , Barasheed et al., 2014; Leung et al., 2020;

MacIntyre et al., 2016; Canini et al., 2010 ). One was an experi-

mental study of 9 influenza patients, which did not measure clin-

ical endpoints ( Johnson et al., 2009 ). Participants with confirmed

influenza coughed onto culture medium wearing a N95 respira-

tor or a mask. No influenza grew on the medium. A trial of 105

sick patients wearing a mask (or no mask) in the household found

no significant difference between arms ( Canini et al., 2010 ). How-

ever, the trial was terminated prematurely and did not meet re-

cruitment targets, so was probably underpowered. One randomised

controlled trial was conducted among Hajj pilgrims, with both well

and sick pilgrims wearing masks, and low rates of ILI were re-

ported among contact of mask pilgrims ( Barasheed et al., 2014 ).

Our randomised controlled trial is the largest available with clinical

endpoints, and studied 245 patients randomised to mask or control

( MacIntyre et al., 2016 ). Compliance was suboptimal in the mask

group and some controls wore masks. The intention to treat anal-

ysis showed no difference, but when analysed by actual mask use,

the rate of infection in household contacts was lower in those who

wore masks ( MacIntyre et al., 2016 ). A trial with an experimental

design was published in April 2020, examining a range of viruses

including seasonal human coronaviruses ( Leung et al., 2020 ). This

howed that coronaviruses are preferentially found in aerosolized

articles compared to large droplets, and could be expelled by nor-

al tidal breathing. Wearing a surgical mask prevented virus from

eing exhaled.

. Discussion

There are more randomised controlled trials of community use

f masks in well people ( Aiello et al., 2012 ; Simmerman et al.,

011 ; Larson et al., 2010 ; Aiello et al., 2010 ; MacIntyre et al., 2009 ;

owling et al., 2008 , Suess et al., 2012 , Cowling et al., 2009 ) than

tudies of the use by sick people (also referred to as “source con-

rol”), and these trials are larger than the few on source control

Johnson et al., 2009 , Leung et al., 2020; MacIntyre et al., 2016 ).

he evidence suggests protection by masks in high transmission

ettings such as household and college settings, especially if used

arly, in some trials if combined with hand hygiene and if wear-

rs are compliant ( Aiello et al., 2012 ; Aiello et al., 2010 ; MacIntyre

t al., 2009 ; Cowling et al., 20 08, 20 09; Suess et al., 2012 ). If masks

rotect in high transmission settings, they should also protect in

rowded public spaces, including workplaces, buses, trains, planes

nd other closed settings. The trial which did not show efficacy

sed influenza as the outcome measure ( Simmerman et al., 2011 ),

hich is a rare outcome, so requires a larger sample size for ade-

uate power and may have been underpowered.

For healthcare workers, the only trials to show a difference

etween respirators and masks demonstrated efficacy for contin-

ous use of a respirator through a clinical shift, but not masks

MacIntyre et al., 2011, 2013 ). The two trials which showed no dif-

erence are widely cited as evidence that masks provide equal pro-

ection as respirators ( Radonovich et al., 2019 , Loeb et al., 2009 ).

owever, without a control arm, the absence of difference between

rms could reflect equal efficacy or inefficacy, and it is not possible

o draw any conclusions about efficacy. The outpatient setting in

he US trial may have had lower exposure risk than the inpatient

etting of other trials. ( Radonovich et al., 2019 ) In both the North

merican trials, the intervention comprised wearing the mask or

espirator intermittently when in contact with recognized ILI or

hen doing a high risk procedure ( Radonovich et al., 2019 , Loeb

t al., 2009 ). The underlying assumption that the majority of infec-

ions in healthcare workers occur during self-identified high-risk

xposures is not supported by any evidence. It assumes health-

are workers can accurately identify when they are risk in a busy,

linical setting, when the majority of infections may occur when

ealthcare workers are unaware of the risk (such as when walking

C.R. MacIntyre and A .A . Chughtai / International Journal of Nursing Studies 108 (2020) 103629 5

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hrough a busy emergency room or ward where aerosolized virus

ay be present). Conversely, infections could occur outside the

orkplace. This could explain the lack of difference if there was

o actual efficacy of either arm and if much of the infection oc-

urs in unrecognized situations of risk either within or outside the

orkplace.

In practice, hospital infection control divides infections into

roplet or airborne spread, and recommends droplet (mask) or air-

orne (respirator) precautions accordingly ( MacIntyre et al., 2017 ).

n a pooled analysis of both healthcare worker trials, we showed

hat continual use of a respirator is more efficacious in protecting

ealthcare workers even against infections assumed to be spread

y the droplet route ( MacIntyre et al., 2017 ). Medical masks did

ot significantly protect against viral, bacterial, droplet or other in-

ection outcomes. However, the summary odds ratio for masks was

ess than one, which suggests a low level of protection. Targeted

se of respirator protected against bacterial and droplet infections,

ut not against viral infections, suggesting viral infections may be

ore likely to be airborne in the hospital setting ( MacIntyre et al.,

017 ).

The five available studies of mask use by sick patients suggest

benefit, but are much smaller trials than the community trials,

wo without clinical endpoints, and with less certainty around the

ndings ( Johnson et al., 2009 , Barasheed et al., 2014; Leung et al.,

020; MacIntyre et al., 2016; Canini et al., 2010 ). Only 3/5 trials ex-

mined clinical outcomes in close contacts ( Barasheed et al., 2014;

acIntyre et al., 2016; Canini et al., 2010 ) and suggest a benefit

Many systematic reviews have been conducted on masks, respi-

ators and other PPE in past ( Cowling et al., 2010 ; Bin-Reza et al.,

012 ; Gralton and McLaws, 2010 ; Gamage et al., 2005 ; Jefferson

t al., 2009 ; Jefferson et al., 2011 ; Jefferson et al., 2008 ; Aledort

t al., 2007 ; Lee et al., 2011 ; Verbeek et al., 2020 ). These reviews

enerally examined multiple interventions (e.g. masks and hand

ygiene etc.), often combined different outcome measures that

ere not directly comparable and were inconclusive. Moreover,

ost of these reviews did not include more recent randomised

ontrolled trials ( Radonovich et al., 2019 , MacIntyre et al., 2015 ).

his systematic review only focuses on masks and respirators and

ontains all new studies.

In summary, there is a growing body of evidence supporting all

hree indications for respiratory protection – community, health-

are workers and sick patients (source control). The largest num-

er of randomised controlled trials have been done for community

se of masks by well people in high-transmission settings such as

ousehold or college settings. There is benefit in the community if

sed early, with hand hygiene and if compliant.

Respirators protect healthcare workers if worn continually, but

ot if worn intermittently in self-identified situations of risk. This

upports the suggestion that the health care environment is a risk

o healthcare workers even when not doing aerosol generating pro-

edures or caring for a known infectious patient. For COVID-19

pecifically, the growing body of evidence showing aerosolisation

f the virus in the hospital ward highlights the risk of inadvertent

xposure for healthcare workers and supports the use of airborne

recautions at all times on the ward ( Santarpia et al., n.d. ; Chia et

l., 2020 ; Liu et al., 2020 ). Further, the rule of 1–2 m of spatial sep-

ration is not based on good evidence, with most research showing

hat droplets can travel further than 2 m, and that infections can-

ot be neatly separated into droplet and airborne ( MacIntyre et al.,

017 ; Bahl et al., 2020 ). In the UK, one healthcare trust found al-

ost one in five healthcare workers to be infected with COVID-19

Keeley et al., 2020 ). The deaths of healthcare workers from COVID-

9 reflect this risk ( Zhan et al., 2020 ). The use of masks by sick

eople, despite being the WHO’s only recommendation for mask

se by community members during COVID-19 pandemic, is sup-

orted by the smallest body of evidence. Source control is prob-

bly a sensible recommendation given the suggestion of protec-

ion and given specific data on coronaviruses showing protection

Leung et al., 2020 ). It may help if visitors and febrile patients wear

mask in the healthcare setting, whether in primary care or hos-

itals. Universal face mask use is likely to have the most impact on

pidemic growth in the community, given the high risk of asymp-

omatic and pre-symptomatic transmission ( He et al., 2020 ).

onflict of Interest

C Raina MacIntyre receives funding from NHMRC (centre for

esearch Excellence and Principal Research Fellowship) and Sanofi

urrently. She has received funding from 3M more than 10 years

go for face mask research.

Abrar Ahmad Chughtai had testing of filtration of masks by 3M

or his Ph.D. more than 10 years ago. 3M products were not used

n his research. He also has worked with CleanSpace Technology

n research on fit testing of respirators (no funding was involved).

unding

C Raina MacIntyre is supported by a NHMRC Principal Research

ellowship, grant number 1137582.

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