SARS-CoV-2, surgeons and surgical masks

Table 1 Primary studies that reported coronavirus disease 2019 among surgeons

Ref.	Study country	Setting	Sample size	Age in years	Male: female	Comorbidity n (%)	Diagnostic TEST	Sample type	Risk of disease	Comment
Hunter et al[16]	United Kingdom	Hospital	1654	Mean 41.7	NR	NR	RT-PCR	Combined nose and throat swabs	Of 1654 HCWs tested, SARS-CoV-2 was detected in 240 (14%)
Jella et al[9]	United States	National data pool	4099	All were aged ≥ 60	NR	NR	NR	NR	For the top most states affected by COVID-19, elderly orthopaedic surgeons aged ≥ 60 years comprised up to 48%
Chow et al[12]	United States, Washington	Phone interview of HCWs with COVID-19	48	Median 43 (range 22-79)	11:37	23 (49.7)	Not specified	NR	Among 48 HCWs with COVID-19 interviewed, 31 (64.6%) worked a median of 2 (range: 1-10) d while being symptomatic	Facemask use by HCWs might prevent transmission from asymptomatic cases
Liu et al[13]	China	University hospital	30	21-59	10:20	NR	RT-PCR	NR	Of all 30 COVID-19 cases, 8 did not wear masks and 6 others wore irregularly
Hughes et al[46]	United States	CDC data pool	571,708 with occupational status known	41 (IQR: 30–53)	79:21	17,838 (44%) had at least one comorbidity	Not specified	NR	Of 571,708 100,570 (22%) were HCWs. Nursing and residential care facilities were the commonest job settings
Jella et al[8]	United States	National data pool	Not mentioned	All were aged ≥ 60	NR	NR	NR	NR	In the 10 states with the highest number of COVID-19 cases older neurosurgical workforce (≥ 60) accounted for 20.6%-38.9%
Ruthberg et al[10]	United States	National data pool	9578	All were aged >60	NR	NR	NR	NR	Of all, 3081 were (32.2%) ENT surgeons aged > 60 years; the proportion by state ranged from 25.9% to 58.8%
Durante-Mangoni et al[14]	Italy	Regional hospital	4 (details were known for only 3)	25-61 (of 3 cases)	2:1 (no details about the 4th case)	NR	RT-PCR	Nasal/or pharyngeal swab	Four nurses infected. No transmission between HCWs wearing surgical masks and inpatients	Masks were beneficial
Jørstad et al[47]	Norway	Regional hospital	6	NR	NR	NR	Not specified	NR	Five ophthalmic surgeons and a ward nurse had COVID-19
Ducournau et al[17]	37 countries (34)	Questionnaire survey	47	NR	NR	NR	Not applicable	NR	42 of 47 (89.4%) wore surgical mask, 12 of 47 (25.5%) wore N95 mask, 32 of 47 (68.1%) wore goggles	This study is about the compliance of surgeons with PPE
Canova et al[15]	Switzerl	Contact racing	21	Median 40 (range 18–62) yr	7:14	NR	RT-PCR	Nasopharyngeal swab	None wore a face mask	None were positive for virus
Guo et al[11]	Wuhan, China	Hospital	24 cases (and 48 controls)	36.1 (25-48)	23:1	1 (4.2%) had a comorbidity	RT-PCR and antibody tests	NR	Only 7 (29.2%) wore a facemask or respirator. Wearing respirator or mask all the time was protective (OR: 0.15, 95%CI: 0.04-0.55)	Orthopaedic surgeons are at risk of COVID-19 and masks are beneficial
Chan et al[48]	Honkong, China	University hospital	14 (10 nurses and 4 other staff)	NR	NR	NR	NR	NR	Fourteen neurosurgery staff contracted COVID-19 following exposure to a patient	Full PPE should be worn during high risk procedures
Ng et al[18]	Singapore	University hospital	41 HCWs exposed to an index patient	NR	NR	NR	RT-PCR	Nasopharyngeal swab	None of the exposed HCWs were RT-PCR positive; 85% wore a surgicalmask, and the rest wore N95 masks	Possibly masks and other standard measures are beneficial

CDC: Centers for Disease Control and Prevention (United States); 95%CI: 95% confidence interval; ENT: Ear, nose and throat (surgeons); HCW: Health care worker; IQR: Interquartile range; NR: Not recorded; OR: Odds ratio; PPE: Personal protective equipment; RT-PCR: Reverse transcriptase polymerase chain reaction.

Table 2 Summary of systematic reviews that provided data on the role of facemask use against respiratory viral infection among health care workers

Ref.	Participants	Intervention(s)	Comparator	Outcome	Comment
Jessop et al[28]	Surgeons	PPE including FFP2/3 and simple surgical masks	Nil	Protection using FFP2/3 respirators is reported to last up to 8 h, whereas protection is to last about 30 min for fluid-repellent masks	Narrative synthesis
Samaranayake et al[19]	Dentists	PPE: masks and respirators	Nil	Wearing layered, face-fitting masks/respirators and protective-eyewear can limit the spread of infection among HCWs; combined interventions such as a face mask and a face shield are better than individual ones	Mostly on HCWs in general, not just dentists
Aggarwal et al[49]	Community dwellers	Facemask and hand washing	Nil	There was no significant reduction in ILI either with facemask alone (pooled effect size: −0.17; [CI95%−0.43–0.10]) or facemask with hand wash (pooled effect size −0.09; [CI95%−0.58 to 0.40])
Liang et al[20]	Diverse participants including HCWs	Facemask	Nil	Use of masks by HCWs can reduce the risk of respiratory virus infection by 80% (OR: 0.20 (95%CI: −0.11–0.37)]
Marson et al[22]	Surgeons	Facemask	Nil	The pooled effect of not wearing facemasks was a risk factor for infection RR: 0.77 (95%CI: 0.62-0.97), a case-control study demonstrated an OR of 3.34 (95%CI: 1.94-5.74) if facemasks were not worn by implant surgeons	The use of facemasks by implant surgeons may be beneficial
Sharma et al[25]	All settings including health care settings	Cloth facemask	Medical grade masks	Cloth facemasks show minimum efficacy in source control than the medical grade mask. The efficacy of cloth face masks filtration varies and depends on material type, and other factors
Santos et al[24]	All settings including health care settings	Cloth facemask	Surgical masks and respirators	Cloth masks presented a considerably lower protection factor [1.9 (95%CI: 1.5-2.3)]; surgical and cloth masks reduced the total number of microbes expelled when coughing wearing a mask, while another study found that neither cloth nor surgical masks effectively filtered the virus expelled through coughing	Cloth masks are not recommendedfor HCWs
MacIntyre and Chughtai[23]	Community, HCWs and sick patients	Face masks	Respirators	RCTs in HCWs 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
Chu et al[21]	Health-care and non-health-care settings	Physical distancing, face masks, and eye protection	N95	Face mask use could result in reduction in risk of infection [aOR: 0.15 (95%CI: 0.07-0.34), RD: -14.3% (95%CI: -15.9 to -10.7)], with stronger association with N95 compared to surgical masks (P = 0.09)	Low certainty of evidence
Bartoszko et al[26]	HCWs	Medical masks	N95	Compared with N95 respirators, the use of medical masks did not increase laboratory-confirmed viral respiratory infection [OR: 1.06 (95%CI: 0.90-1.25)]. Only one trial evaluated coronaviruses separately and found no difference between the two groups (P = 0.49)	Low certainty of evidence but only RCTs are included
Chou et al[27]	Health-care and community settings	Surgical, N95, andcloth	N95 or no mask	In health care settings, observational studies found that risk for infection with SARS-CoV-1 probably decreased with mask use and possibly decreased more with N95 mask use. RCTs found, N95 and surgical masks were probably associated with similar risks for ILI and laboratory-confirmed viral infection	Evidence on effectiveness of facemask is stronger in health care than communitysettings

aOR: Adjusted odds ratio; 95%CI: 95% confidence interval; HCW: Health care worker; ILI: Influenza-like illness; OR: Odds ratio; PPE: Personal protective equipment; RCTs: Randomised controlled trial; RD: Risk difference.