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Evidence Table  
 
All studies which are critically appraised as part of the literature review are assigned a grade of evidence based on the SIGN 50 methodology 
grading system (SIGN, 2004), which allows scientific studies to be assessed for quality using a number of reviewing forms (available from the 
SIGN website - http://www.sign.ac.uk). The main conclusions from the studies are summarized along with a brief description of the study 
quality in an Evidence Table. Studies, which have sufficient quality and specifically answer a defined research question are grouped together to 
enable formation of a “considered judgment” based on this information. This “considered judgment” is then used as the basis for formulation of 
recommendations.  
 
This system allows formulation of recommendations supported by good quality observational studies in the case when RCTs are not available 
for practical or ethical reasons, as is generally found in infection control literature.  
 
Levels of evidence 
 
The following grades were given to the papers included in this evidence table: 
 
1++   High quality meta analyses, systematic reviews of RCTs, or RCTs with a very low risk of bias 
 
1+  Well conducted meta analyses, systematic reviews of RCTs, or RCTs with a low risk of bias 
 
1-  Meta analyses, systematic reviews of RCTs, or RCTs with a high risk of bias 
 
2++  High quality systematic reviews of case-control or cohort studies  
High quality case-control or cohort studies with a very low risk of confounding, bias, or chance and a high probability that the relationship is causal 
 
2+  Well conducted case control or cohort studies with a low risk of confounding, bias, or chance and a moderate probability that the relationship is causal 
 
2-   Case control or cohort studies with a high risk of confounding, bias, or chance and a significant risk that the relationship is not causal 
 
 Non-analytic studies, e.g. case reports, case series 
 
4  Expert opinion 
 
- 1 - 

Question: When should patients wear a FRSM? (SICPs) 
Study 
Study type 
Evidence level 
Intervention 
Comparison 
Outcome measures 
 
 
 
Ref 1387. Baig, S, 
Patients wearing a 
 
 
Rashid, T and Saleem, 
mask when being 
 
 
M. Protection from 
treated for epistaxis 
Patients not wearing a 
 
blood aerosol 
via cautery, anterior 
mask when being 
Number of blood 
contamination when 
nasal packing or 
treated for epistaxis 
splatters on physicians 
managing epistaxis: a 
RCT with high risk of 
anterior/posterior 
via cautery, anterior 
eye shield 

study of the 
bias 
packing. 
nasal packing or 
effectiveness of a 
 
anterior/posterior 
patient mouth mask. 
(Classic Surgical 
packing. 
2015. Ear, Nose and 
Mask – Kimberley 
 
Throat Journal. Vol 94 
Clark ≥96% (BFE), 
(9) p394-398. 
≥97% (PFE) 
 
Assessment of evidence:  
 
 
4 blood splatters (13.3%) in mouth mask group  
8 blood splatters (26.7%) in control group 
 
No p-values or confidence intervals to indicate levels of statistical significance. Participants were randomly allocated but authors do not indicate 
how this was done. Lack of information regarding the characteristics of participants.  
 
This study suggests that the wearing of surgical masks by epistaxis patients during treatment may reduce the number of blood splashes to HCW 
facial PPE. However, due to limited information and small sample sizes, conclusions cannot be definitively drawn.  
 
It is also unclear whether the need for patients to wear a surgical mask in this scenario is necessary if facial PPE provides adequate protection. This 
study supports the recommendation that mask/eye protection be worn by HCWs when bodily fluid splashes are anticipated. 
 
This study had a high risk of bias as the blood splatters were counted by the physician who had just removed their own mask.  Furthermore, this 
 
- 2 - 

method relied on the visual capabilities of the physician alone and this lacks scientific rigour. 
 
 
Ref 5541. Raad, I, 
Hanna, H, Osting, C, 
Nosocomial infection 
Hachem, R, Umphrey, 
with invasive 
J, Tarrand, J, 
pulmonary 
Kantarjian, H and 
aspergillosus with 
Bodey, G. P. Masking 
symptoms appearing 
of neutropenic 
Use of ‘high 
Non-mask use by 
at least 14 days after 
patients on transport 
efficiency’ masks by 
patients when 
admission. 
from hospital rooms is 
patients when 
transported out of 
 
associated with a 
Observational study 

transported out of 
their rooms during 
Results of air 
decrease in 
their rooms during 
hospital construction 
sampling. 
nosocomial 
hospital construction 
works. 
 
aspergillosis during 
works. 
Rates of IPA infection 
construction. 2002. 
of those with 
Infection Control and 
haematological 
Hospital 
malignancy within the 
Epidemiology. Vol 23 
community. 
(1) p41-43 
 
 
Assessment of evidence:  
 
Graded as level 4 evidence as a ‘concise communication’ and therefore not peer-reviewed. 
 
The incidence of nosocomial IPA decreased from 0.73 per 1000 hospital patient days to 0.24 per 1000 hospitalised patient days (p=<0.001). 
Incidence decreased significantly for both leukaemia patients (p=<0.001) and bone marrow transplant patients (p=0.02). This was despite a 
significant increase in community acquired IPA in those with haematological malignancy (p=0.002) and a significant increase in aspergillus 
positive indoor air samples from period 1 to period 2 (p=0.003). Authors were not aware of any other confounding intervention that could have 
impacted on IPA incidence. 
 
Unclear as to what specific type of surgical mask was used but authors state that masks filter to a particle size of 0.1µm and are “able to filter 99% 
 
- 3 - 

of Aspergillus organisms”. Total patient numbers studied is not provided, results are given as per 1000 hospital patient days. The intervention was 
not applied during the same environmental conditions as masks were not worn during a period of lesser construction and worn during a period of 
heavy construction. However, intuitively, this should have resulted in an increase in IPA cases not a decrease. 
 
This study weakly supports the recommendation that immunocompromised patients who are being transported out with their room during a period 
of hospital construction should be given a surgical mask to wear if it can be tolerated. 
 
Question: When should patients wear a FRSM? (TBPs) 
Study 
Study Type 
Evidence Level 
Intervention 
Comparison 
Outcome measure 
 
 
Nicola J Rowbotham, Sally 
Includes an 
Systematic review 
C Palser, Sherie J Smith & 
assessment of 
assessing the evidence 
3 included studies. Two 
Alan R Smyth. Infection 
evidence 
 
base behind different 
studies found face masks to 
prevention and control in 
concerning the 
Systematic 
 
infection control 
be effective in reducing 
cystic fibrosis: a systematic 
efficacy of face 
 
Review 
2+ 
precautions used to 
aerosol PA load and an RCT 
review of interventions. 
masks in 
 
prevent infection in 
found no difference in exam 
2019. Expert Review of 
reducing 
cystic fibrosis 
room contamination rate.  
Respiratory Medicine, 13:5, 
infection for 
patients. 
425-434 
CF patients. 
 
Assessment of evidence: 
 
The systematic review was well conducted, however, due to the low amount/quality of studies identified, meta-analysis was not conducted. There 
was no assessment of publication bias. Meta-analysis of the three studies identified was not done/appropriate and although one was an RCT all 
three measured indirect indicators of infection transmission prevention eg. PA aerosol loads/room contamination. All three studies have been 
included in the critical appraisal phase of this surgical mask review; Wood et al 2018, Stockwell et al 2018 and Zuckerman et al 2015.  
 
 
This systematic review was completed to a reasonable standard but lacked some key featured that allow for clear interpretation of the results 
found.  The authors did not asses risk of bias in the included publications and there was a lack of detail on the methods applied to combine 
individual study findings.  For these reasons the evidence level applied to this systematic review reflects these lacking elements. 
 
 
 
- 4 - 

Surgical mask 
 
 
Wood, M. E, Stockwell, R. 
(TECNOL 
Uncovered 
1. Percentage of participants 
E, Johnson, G. R, Ramsay, 
Fluidshield 
coughing and 
with detectable P. aeruginosa 
K. A, Sherrard, L. J, Jabbour, 
Fog-Free Surgical 
talking 
following each intervention 
N, Ballard, E, O'Rourke, P., 
Mask; Kimberly-
measured 2m from source 
Kidd, T. J, Wainwright, C. E, 
Clark Professional) 
 
Knibbs, L. D, Sly, P. D, 
(ASTM Level 3).  
2. Log¹º number of P. 
Morawska, L and Bell, S. C. 
 
aeruginosa CFUs collected 
Face masks and cough 
N95 respirator (N95 
2m from source. 
Controlled trial 
etiquette reduce the cough 
 3 
Particulate 
 
 
study 
aerosol concentration of 
Filter Respirator; 
3. Percentage reduction in 
pseudomonas aeruginosa in 
Kimberly-Clark). 
aerosol P. aeruginosa 
people with cystic fibrosis. 
 
concentration (log-
2018. American Journal of 
Masks worn by CF 
transformed CFUs) 
Respiratory and Critical Care 
patients chronically 
Medicine. Vol 197 (3) p348-
infected with P. 
355 
aeruginosa for 5 
 
minute periods of 
coughing or talking.  
Assessment of evidence:  
This study showed a statistically significant reduction in numbers of P. aeruginosa CFU detected in aerosols, 2 meters from the source when 
surgical masks were worn during coughing compared to uncovered coughing. This study also showed that the number of P. aeruginosa CFUs 
produced during uncovered talking is comparable to that produced when talking whilst wearing a surgical mask. 
Limitations of this study include the inability to directly link the number of CFUs detected to risk of transmission of infection. The masks used are 
slightly different to those employed in the UK as they are ASTM level 3 masks. These have greater fluid resistance than an type IIR mask but the 
same BFE of >98%. Masks were only worn for 9 minutes and the reductive effects provided after this time are unknown. 
This study adds to the evidence base for coughing CF patients to wear surgical masks when in communal areas with other CF patients although is 
perhaps not of a high enough quality/size to support a change to recommendations. 
 
“Johnson et al., who 
 
 
investigated how surgical 
Expert opinion 

 
 
 
Ref 3069. Bunyan D, Ritchie 
masks and N95 respirators, 
L, Jenkins D and Coia JE. 
worn by patients with 
confirmed influenza, would 

Respiratory and facial 
 
- 5 - 

protection: a critical review 
prevent the generation of 
of recent literature. 2013. 
infectious airborne particles. 
Journal of Hospital Infection. 
Surgical masks and N95 
Vol 85 p165-169. 
respirators appeared to be 
equally and highly effective 
in filtering out influenza-
contaminated particles when 
worn by infected patients.42 
This small study did not 

investigate whether masks or 
respirators worn by patients 

reduced the numbers of 
cross-infection events in a 
real clinical setting, which 
would be the decisive test for 
this approach.” 

Assessment of evidence:  
 
This expert opinion is based on a review. The document provides guidance on surgical masks and respirators. It advises on the standards that both 
these types of masks should meet in the UK, when they should be worn, how they should be fit checked/tested if necessary and how they should be 
removed and disposed of. 
 
It refers to relevant health and safety/governmental legislation. 
 
Caution is advised as this guidance was published in 2014 and some aspects may be out of date. 
 
NOT TO BE USED FOR FORMAL RECOMMENDATIONS 
 
 
“relative risk for any virus 
Ref ID 6107 
Participants donned a 
detection with mask versus 
Milton, D. K., Fabian, M. P., 
Controlled 
ear-loop surgical 
Participants did 
without a mask was 0.85 and 
Cowling, B. J., Grantham, M. 
experimental 

mask (Kimberly-
not don a 
 
L., McDevitt, J. J. 2013. 
study 
Clark, Roswell, 
surgical mask 
borderline statistically 
Influenza virus aerosols in 
significant (CI 0.72 to 1.01; 
GA). 
human exhaled breath: 
McNemar’s test p =0.06).” 
 
- 6 - 

particle size, culturability, 
(p: 2) 
and effect of surgical masks. 
 
PLoS Pathogens. Volume 
9(3). p: e1003205 
“The geometric mean copy 
 
number in the fine particle 
 
fraction without a facemask 
 
was 110 (95% CI 45 to 260) 
and the facemasks produced 
a 2.8 fold reduction in copy 
number (95% CI 1.5 to 5.2, 
p= 0.001)”
(p: 2) 
 
“Combining the coarse and 
fine fractions, we detected 
viral RNA in 29 (78%) 
subjects when wearing 
facemasks and 35 (95%) 
when not wearing facemasks 
(McNemar’s test p= 0.01). 
Surgical masks produced a 
3.4 (95% CI 1.8 to 6.3) fold 
reduction in viral copies in 
exhaled breath.” 
(p:2) 
 
“This finding supports 
current Centers for Disease 
Control and Prevention 
recommendations that 
healthcare facilities 
encourage patients with 
influenza-like illness to don 
surgical facemasks as one 
component of an influenza 
infection control program”
 
(p:3) 
 
- 7 - 

Assessment of evidence:  
 
Low quality, small study that lacks validity, reliability and generalisability in relation to answering the research question it is most relevant to.  
However, as the authors state , the findings do support the CDC recommendation for healthcare facilities to encourage use of facemasks by patients 
with ILI as part of a wider IPC effort. 
 
Limitations: 
 
  The sampler used in the study was specifically for fine and ultrafine particles which would therefore mean it would not detect large droplets 
(>50 µm).  
  Sample was of volunteers from the community, most of whom were either students or staff at the university of Massachusetts.  Not 
healthcare professionals. 
  No further details of participant demographics assessed 
  Lacks validity and generalisability 
  Measured results of forced coughs 
  the mask description does not include enough detail to confirm the exact mask model and associated properties of the mask (FRSM?) 
 
 
 
“When transporting a patient 
with symptoms of influenza, 
the patient should be 
 
encouraged to wear a 
Ref XX. Department of 
surgical mask to minimise 
Health and Health Protection 
droplet dispersal. The mask 
Agency. Pandemic influenza: 
should be worn throughout 
Summary infection control 
Guidance 

 
 
the period of transport.” 
 
guidance for ambulance 
 
services during an influenza 
“If the patient cannot tolerate 
pandemic. 2009.  
a mask, good respiratory 
 
hygiene should be 
 
encouraged and a tissue or 
similar can be offered to hold 
against their mouth and 
nose to ‘catch’ secretions 
 
- 8 - 

from coughing, sneezing or 
blowing the nose.” 
 
 
HICPAC and Centres for 
Disease Control. Core 
Infection Prevention and 
Expert 
Control Practices for Safe 
opinion/consens

 
 
 
 
Healthcare Delivery in All 
us 
Settings – Recommendations 
of the Healthcare Infection 
Control Practices Advisory 
Committee. 2017. 
Assessment of evidence:  
 
“Prompt patients and visitors with symptoms of respiratory infection to contain their respiratory secretions and perform hand hygiene after contact 
with respiratory secretions by providing tissues, masks, hand hygiene supplies and instructional signage or handouts at points of entry and 
throughout the facility” 
 
 
 “Surgical/procedure 
masks are used for 
several different 
purposes, 

Ref XX. Occupational 
including the 
Safety and Health Act 
following: […] 
(OSHA). Guidance on  Guidance / Expert 
Placed on sick people 
Preparing Workplaces 

 
 
opinion 
to limit the spread of 
for an 
infectious respiratory 
Influenza Pandemic. 
secretions to others.” 
2009.  
(pp 21) 
 
 
 
- 9 - 

This document specifies from the outset that the information provided is purely advisory guidance and is not a standard or a regulation.  This differs 
from the legal obligations of employers and employees that are found within other OSHA documents such as the OSHA standards or the 
Occupational Safety and Health Act (OSH Act). 
 
Caution is given regarding the appropriate use of both surgical masks and respirators: 
 “Surgical masks are not designed or certified to prevent the inhalation of small airborne contaminants. These small airborne contaminants are too 
little to see with the naked eye but may still be capable of causing infection. Surgical/procedure masks are not designed to seal tightly against the 
user’s face. During inhalation, much of the potentially contaminated air passes through gaps between the face and the surgical mask, thus avoiding 
being pulled through the material of the mask and losing any filtration that it may provide. Their ability to filter small particles varies significantly 
based upon the type of material used to make the surgical mask, and so they cannot be relied upon to protect employees against airborne infectious 
agents.” 
(pp 22) 
 
“Note: Additional respirator and surgical mask guidance for healthcare workers has been developed and is available at 
www.pandemicflu.gov/plan/healthcare/maskguidancehc.html. This document, “Interim Guidance on Planning for the Use of Surgical Masks and 
Respirators in Health Care Settings during an Influenza Pandemic,” provides details on the differences between a surgical mask and a respirator, 
the state of science regarding influenza transmission, and the rationale for determining the appropriate protective device.” 
(pp 26) 
Medical masks should be 
part of a number of IPC 
 
supplies that are accessible 
Ref XX. World Health 
within the healthcare 
Organisation (WHO). 2014. 
environment. 
Infection prevention and 
 
control of epidemic-and 
“In people with ARIs, 
pandemic-prone acute 
encourage the use of 
respiratory infections in 
respiratory hygiene (i.e. 
health care. [Online]. 
Agree: 
Guidance 
NA 
NA 
covering the mouth and nose 
Available at: 
recommend 
during coughing or sneezing 
https://apps.who.int/iris/bitstr
with a medical mask 
eam/handle/10665/112656/9
[surgical or procedure 
789241507134_eng.pdf;jsess
mask], cloth mask, tissue, 
ionid=90E49145E816EB709
sleeve or flexed elbow), 
14AF47FFF7EC42E?sequen
followed by hand hygiene, to 
ce=1 
reduce the dispersal of 
 
respiratory secretions 
containing potentially 

 
- 10 - 

infectious particles (Strong 
recommendation, very low 
quality of evidence)…”
 (pp 
31) 
 
It is recommended that 
patients with Acute 
Respiratory Infection or TB 
should always don a medical 
mask when outside of 
isolation areas. 
 
“Encourage the use of 
medical masks by patients 
with ARI during transport or 
when care is necessary 
outside of the isolation room 
or area”
 (pp 18) 
 
 

Assessment of evidence:  
 
Within this document a medical mask is defined as: Medical mask  
Also known as a surgical or procedure mask. As personal protective equipment, a facial mask is intended to protect caregivers and health-care 
workers against droplet-transmitted pathogens, or to serve as part of facial protection for patient-care activities that are likely to generate splashes 
or sprays of blood, body fluids, secretions or excretions (Annex A provides details of usage and standards for medical masks). In this document, the 
term refers to disposable masks only.”
 (pp xviii). 
 
A.2.3 Medical mask standards  
Medical masks protect the wearer's nose and mouth from inadvertent exposures (e.g. through splashes) to blood and other body fluids. However, 
there are no minimum standards or standardized testing methods for mask filter efficiency, and available masks vary widely in the efficiency of 
their filters. As an example of standards, the Association of Perioperative Registered Nurses recommends that surgical masks filter particles of at 
least 0.3 μm for regular use and 0.1 μm for laser use (i.e. to protect the wearer against laser smoke), or have 90–95% bacterial filtration efficiency. 
Furthermore, surgical masks are classified as medical devices in Europe and the US and are regulated appropriately. For example, the US Food 
and Drug Administration (FDA) standards for surgical masks are as follows: 1  

 
- 11 - 

• Fluid resistance:  
– American Society for Testing and Materials (ASTM) F 1862–00a: standard test method for resistance of surgical mask to penetration by synthetic 
blood.  
• Filtration efficiency:  
– particulate filtration efficiency (PFE) – 0.1 μ polystyrene latex sphere;  
– bacterial filtration efficiency (BFE) – ASTM F 2101–01: standard test method for evaluating the BFE of surgical masks using a biological 
aerosol of Staphylococcus aureus.  
• Air exchange (differential pressure, delta-P):  
– measure of breathability and comfort of surgical masks.  
• Flammability:  
– Class 1 and Class 2 flammability rating material for use in the operating room (OR);  
– Class 4 flammability rating is not appropriate for use in the OR (would be labelled as “not for OR use”).  
• Biocompatibility.” 
(pp 41) 
 
“Respiratory hygiene/cough 
etiquette (source 
containment of infectious 

Siegel, J. D., Rhinehart, E., 
respiratory secretions in 
Jackson, M. and Chiarello, L.  
symptomatic patients, 
et al. Health Care Infection 
beginning at initial point 
Control Practices Advisory 
of encounter, eg, triage and 
Committee (HICPAC).  
reception areas in 
2007. 2007 guideline for 
emergency departments 
isolation precautions: 
AGREE: 
and physician offices)” … in 
Guidance 
NA 
NA 
preventing transmission of 
Recommend 
this instance healthcare 
infectious 
workers should … 
agents in health care settings. 
“Instruct symptomatic 
American Journal of 
persons to cover mouth/nose 
Infection Control. 35:S65-
when sneezing/ 
164.  
coughing; use tissues and 
 
dispose in no-touch 
receptacle; observe 
hand hygiene after soiling of 
hands with respiratory 

 
- 12 - 

secretions; wear 
surgical mask if tolerated or 
maintain spatial separation, 
.3 feet if 
possible.”
 (pp S74) 
 
Recommendation: surgical 
mask when: “placed on 
coughing patients to limit 
potential dissemination of 
infectious respiratory 
secretions from the patient to 
others (ie, respiratory 
hygiene/cough etiquette).”
 
(S99) 
 
Transportation of patients: 
“When transport is 
necessary, applying 
appropriate 
barriers on the patient (eg, 
mask, gown, wrapping 
in sheets or use of 
impervious dressings to 
cover the affected 
areas) when infectious skin 
lesions or drainage 
are present, consistent with 
the route and risk of 
transmission.”
 (pp S103) 
Assessment of evidence: 
 
This set of recommendations is supported by a review of scientific literature. It is split into multiple parts many of which contain relevant 
information to answer this RQ. 
 
 
- 13 - 

 
Ref XX. Internal Clinical 
Guidelines Team. 
Tuberculosis – Prevention, 
diagnosis, management and 
AGREE: 

service organisation. NICE 
Guidance 
 
 
Recommend 
NG33. Methods, evidence 
 
and recommendations 
(2016).  
 
Assessment of evidence:  
 
“1.5.1.12 Explain to inpatients with suspected infectious or confirmed pulmonary or 
laryngeal TB that they will need to wear a surgical mask in the hospital 
whenever they leave their room. Ask them to continue wearing it until they have 
had at least 2 weeks of treatment. [2016]”
 (pp 45) 
 
 
Ref 1879. Coia JE, Ritchie L 
and Fry C. Use of respiratory 
and facial protection. 2014. 
Nursing Times. Vol 110 (4) 
p18-20. 
 
AND 
 
 
Expert 

 
 
 
Ref 2987. J.E. Coia, L. 
consensus 
 
Ritchie, A. Adisesh, C. 
Makison Booth, C. Bradley, 
D. Bunyan, G. Carson, C. 
Fry, P. Hoffman, D. Jenkins, 
N. Phin, B. Taylor, J. S. 
Nguyen-Van-Tam, M. 
Zuckerman, The Healthcare 
Infection Society Working 
 
- 14 - 

Group on Respiratory and 
Facial Protection.  Guidance 
on the use of respiratory and 
facial protection. Journal of 
hospital infection 85(2013) 
165-169 
 
AND 
 
Ref 3069. Bunyan D, Ritchie 
L, Jenkins D and Coia JE. 
Respiratory and facial 
protection: a critical review 
of recent literature. 2013. 
Journal of Hospital Infection. 
Vol 85 p165-169. 
Ref 1879 is a summary of ref 2987 and ref 3069 was the review that informed ref 2987. 
 
To protect others from the wearer as a source of infection. 
 
This expert consensus provides guidance on surgical masks and respirators. It advises on the standards that both these types of masks should meet 
in the UK, when they should be worn, how they should be fit checked/tested if necessary and how they should be removed and disposed of. 
 
It refers to relevant health and safety/governmental legislation. 
 
Caution is advised as this guidance was published in 2014 and some aspects may be out of date. 
Epic3: National 
Evidence-Based 
Guidelines for 
Preventing 
Guidance/expert 
AGREE: recommend 
Healthcare-Associated 
 
 
 
opinion 
(but level 4 here) 
Infections in 
NHS Hospitals in 
England. H.P. 
Loveday, J.A. Wilson, 
 
- 15 - 

R.J. Pratt, M. 
Golsorkhi, A. Tingle, 
A. Bak, J. Browne, J. 
Prieto, M. Wilcox. 
2014. Journal of 
Hospital Infection. S1-
S70 
 
Authors state that healthcare workers may use “standard fluid repellent masks to prevent respiratory droplets from the mouth or nose being expelled 
into the environment”, although this is not included in their formal recommendations. This would suggest that masks worn by symptomatic patients 
to prevent dissemination of infectious particles should be fluid resistant but this is based on interpretation and is not specifically outlined in any 
sources and so has been given a level 4 (expert opinion) grading. 
 
Respiratory droplet 
 
Control: 
Viral load (log10 virus 
and respiratory 
Leung N.H.L. et al. 
Respiratory droplets 
copies per sample) 
aerosol samples were 
Respiratory virus 
and respiratory 
detected in aerosol 
collected for 30 mins 
shedding in exhaled 
aerosols samples were  samples and droplet 
Randomised 
with participants 
breath and efficacy of 
1- 
collected for 30 mins 
samples. 
controlled trial 
wearing a type II 
face masks. Nature 
whilst they sat 
 
mask whilst they sat 
Medicine, 3 April 
naturally breathing 
Detection of virus in 
naturally breathing 
2020. 
with allowance for 
aerosol samples and 
with allowance for 
 
any natural coughing. 
droplet samples. 
any natural coughing. 
 
 
Effect of wearing a surgical mask (equivalent to type II) on detection of viral seasonal influenza, seasonal coronavirus or seasonal rhinovirus 
particles detected on exhalation from infected participants. Respiratory droplets or respiratory aerosols were collected for 30 mins with participants 
either wearing or not wearing a mask whilst they sat naturally breathing with allowance for any natural coughing. Of 246 - 122 randomised to not 
wearing a facemask, 124 randomised to wearing a facemask. Of 246 participants – 111 had seasonal coronavirus (n=17), influenza (n=43) or 
rhinovirus (n=54). [3 participants had multiple infections]. 
 
No coronavirus virus was detected in respiratory droplets or aerosols collected from participants wearing face masks (n=11), this detection and viral 
load difference was significant in aerosols (p=0.04). Surgical face masks significantly reduced detection and viral load of influenza virus RNA in 
respiratory droplets. While not wearing a mask, viral RNA was only identified from 30% (corona), 26% (influ) and 28% (rhino) of respiratory 
droplet samples and 40% (corona), 35%(influ) and 56% (rhino) of aerosol samples. Reduced detection of virus is an indirect measure of reduced 
 
- 16 - 

transmission from symptomatic patients. 
 
Authors report that viable influenza particles were detected in aerosols following collection of samples from both those wearing and not wearing 
masks highlighting this as a potential mode of transmission. Among the eight participants who had influenza virus detected by RT–PCR from 
without-mask aerosols, five were tested by viral culture and four were culture-positive. Among the six participants who had influenza virus detected 
by RT–PCR from with-mask aerosols, four were tested by viral culture and two were culture-positive.  
 
It is unclear as to the impact that widespread use of this intervention would have, especially as it appears that a proportion of patients may not 
exhale any detectable virus whilst infected. 
 
This study suggests that type II surgical masks may significantly reduce coronavirus virus (exhaled from symptomatic mask wearers in the form of 
droplets and/or aerosols) to undetectable levels. However, sample sizes are too small to draw definitive conclusions.   
This study suggests that type II surgical masks may significantly reduce influenza virus (exhaled from symptomatic mask wearers in the form of 
droplets). However, sample sizes are too small to draw definitive conclusions.   
This study suggests that type II surgical masks may not be effective in significantly reducing rhinovirus virus (exhaled from symptomatic mask 
wearers in the form of droplets and/or aerosols). However, sample sizes are too small to draw definitive conclusions.   
This study suggests that type II surgical masks may not be effective in significantly reducing influenza virus (exhaled from symptomatic mask 
wearers in the form of aerosols). However, sample sizes are too small to draw definitive conclusions.   
 
This study is limited and provides very weak evidence that surgical face masks could be used by symptomatic people to reduce onwards 
transmission of respiratory pathogens. 
 
 
 
 
Ref XX. DoH and 
HPA 2009. 
PANDEMIC (H1N1) 
2009 INFLUENZA 
Guideline 

 
 
 
A summary of 
guidance for infection 
control in healthcare 
settings. 
 
“The provision of surgical masks to patients with suspected or confirmed pandemic influenza to be worn from the point of assessment or triage in 
 
- 17 - 



any healthcare setting (except when in a dedicated influenza area) should be considered.” 
 
“In common waiting areas or during transport, symptomatic patients may wear surgical masks to minimise the dispersal of respiratory secretions 
and reduce environmental contamination.” 
 
 
 
 
 
 
 
 
 
 
 
 
 

Health  
Protection  
Network  
                                                                                   
                                                       
 
Considered judgement form   
 
 
 
Question: When should patients wear a FRSM? (SICPs) 

Evidence Table Ref: 6a 
 
1. Volume of Evidence  - Quantity of evidence on this topic and quality of method 
 
- 18 - 

 
1 low quality RCT which assesses the merit of patients wearing surgical masks during treatment of epistaxis 
1 observational study which assesses the impact of immunocompromised patients wearing masks when being transported out with their rooms during 
constructions periods. 
 
2. Applicability – in Scotland 
 
Applicable 
 
3. Generalisability  - How reasonable it is to generalise from the available evidence 
 
Due to the low number of studies it would be inappropriate to generalise from the available evidence. 
 
4. Consistency - Degree of consistency demonstrated by the available evidence 
 
N/A 
 
5. Potential Impact of the intervention 
 
Asking patients to wear masks may be unnecessary, impact on pt comfort, inhibit communication and be a waste of resources if not required. 
 
6. Other factors to consider while assessing the evidence base 
 
 
7. Evidence Statement – synthesis of the evidence relating to this question 
Evidence level 
 
- 19 - 

 
Scientific findings are limited and based on observational studies. Recommendations are based on expert opinion and the 
concept that masks are low cost interventions therefore recommending their use may be based on a precautionary 
approach  
 
 
Leukaemia and bone marrow transplant patients, who are being transported out with their room, during a period of 

hospital construction, should be given a surgical mask to wear if it can be tolerated. 
 
 
As there is only one study to support each patient mask wearing event, conclusions and thus recommendations cannot 
currently be drawn.  
 
8. Recommendation -  
Grade of Recommendation 
 
No recommendations can currently be made regarding patients wearing surgical masks in line with SICPs. 
N/A 
 
 
 
Question: When should patients wear a FRSM? (TBPs) 

Evidence Table Ref: 6b 
 
1. Volume of Evidence  - Quantity of evidence on this topic and quality of method 
 
There is a paucity of evidence on when patients should wear surgical masks.  However, there does appear to be some consensus between the Guidance 
available from UK sources which focus on prevention of spreading of the aerosol or droplet infection whilst the patient is accessing communal areas (out of 
their room). 
 
1 systematic review was inconclusive regarding need for CF patients to wear surgical masks in communal areas (studies assessed were indirect measures of 
infection control) 
1 controlled experimental study suggested that masks can filter out/reduce influenza particles produced by infectious patients 
1 piece of UK guidance (B) gave advice re mask wearing by TB patients 
1 UK expert opinion/guidance (C), 2 x US expert opinion guidance (C), WHO guidance (B) and US guidance (B) gave advice re: mask wearing by patients 
known or suspected to be infected with droplet transmitted pathogens. 
 
 
2. Applicability – in Scotland 
 
- 20 - 

 
Most studies are low quality, conducted in the US or experimental in nature. Expert opinion is partly derived from UK based authors. 
 
3. Generalisability  - How reasonable it is to generalise from the available evidence 
 
Due to the low quality/experimental nature of the studies it is inappropriate to generalise from the available evidence. 
 
4. Consistency - Degree of consistency demonstrated by the available evidence 
 
Recommendations are limited but fairly consistent. 
 
5. Potential Impact of the intervention 
 
Asking patients to wear masks may be unnecessary, impact on comfort, inhibit communication and be a waste of resources if not required. 
 
6. Other factors to consider while assessing the evidence base 
 
 
7. Evidence Statement – synthesis of the evidence relating to this question 
Evidence level 
 
Scientific findings are limited and based on observational/experimental studies. Recommendations are based on expert 
 
opinion and the concept that masks are low cost interventions therefore recommending their use may be based on 
3/4 
precautionary measures 
 
 
8. Recommendation -  
Grade of Recommendation 
 
- 21 - 

If it can be tolerated, an FRSM may be worn by a patient known or suspected to be infected with a microorganism spread 
by the droplet route during patient transportation from one clinical area to another.  
 
Patients with pulmonary or laryngeal Tuberculosis should be made aware by the healthcare team caring for them that a 
B/C 
surgical mask should be worn when they leave their room and that this precaution applies until they have received a 
minimum of 2 weeks of treatment (NICE 2016). 
 
 
 
- 22 -