Table 2.

Study characteristics of mask use in health care workers to prevent viral respiratory tract infections

Jacobs et al,28 2009 (no)Japan, tertiary care hospitalHealth care workers (mean 35.5 y)33 (32)NAMask (17), no mask (15)Health care workers (not sick)Health care workers wear masks while on hospital property and performing their roles84.3% of participants self-reported “full compliance,” with the remaining complying 79% to 99% of the time (applies to both mask use and nonuse)
Loeb et al,29 2009 (no)Canada, tertiary hospitalsNurses (mean 36 y)446 (422)NASurgical masks (212), N95 masks (210)NursesWhen caring for patients with febrile respiratory illnessAll 11 participants allocated to surgical masks wore them when caring for patientsadmitted to unit in droplet precautions for influenza
MacIntyre et al,30 2011 (yes)China, hospital (ED and respiratory wards)Nurses, doctors, ward clerks (mean 34 y)1441 (1441)Cluster: unit of randomization was hospital (15 hospitals involved, 5 per study arm)Surgical masks (492), N95 fit-tested masks (461), N95 masks not fit-tested (488)Health care workersEvery shift (given 3 surgical masks daily or 2 N95 masks daily)Worn >80% on working days: surgical, 76% (5 h/day); N95 fit, 74% (5.2 h/day); N95 no fit, 68% (4.9 h/day)
MacIntyre et al,31 2013 (yes)China, hospitals (ED and respiratory wards)Nurses, doctors (mean 33.1 y)Surgical mask = 572 (572), targeted use of N95 = 561 (516), N95 = 581 (581), total = 1669 (166)68 wards at 19 sitesSurgical masks (572), targeted use of N95 masks (516), N95 masks (581)Nurses, doctorsAll the time (surgical masks), as needed (targeted N95 masks), all the time (N95 masks)66% for surgical masks, 82% for N95 targeted masks, 57% for N95 masks
MacIntyre et al,32 2015 (yes)Vietnam, hospitals (ED, ICU, ID or respiratory wards, pediatric ward)Nurse or doctor (mean 36 y)1607 (1607)74 wards at 14 sitesSurgical masks (580), cloth masks (2-layer cotton) (569), control (458)—“standard practice” of mask useNurses or doctorsSurgical masks: all the time on shift; cloth masks: all the time on shift; control: standard practiceSurgical masks 56.6%, cloth masks 56.8%, standard practice 23.6%
Radonovich et al,33 2019 (yes)US, outpatient sites (clinics, primary care clinics, EDs)Health care personnel (mean 43 y)5180 health care personnel seasons = 4051 participants (5180 seasons)380 clusters at 137 sitesSurgical masks (2668 person-seasons), N95 masks (2512 person-seasons)—note that 1 person could be in different arms each of the 4 seasonsThose involved in direct patient careWhenever positioned within 6 ft of a patient with suspected or confirmed respiratory illnessN95: 65.2% always, 24.2% sometimes; surgical: 65.1% always, 25.1% sometimes
  • ED—emergency department, ICU—intensive care unit, ID—infectious disease, NA—not applicable, RCT—randomized controlled trial, US—United States.