Randomized controlled trials |
Loeb et al., 2009 (11) | 8 hospitals in Ontario, Canada: emergency departments, acute medical units and pediatric units | 446 nurses; individual-level randomization |
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Intervention: targeted use, fit-tested N95 respirator Control: targeted use, surgical mask
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Noninferiority trial Detection of influenza A and B, respiratory syncytial virus metapneumovirus, parainfluenza virus, rhinovirus–enterovirus, coronavirus and adenovirus
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MacIntyre et al., 2011/2014 (12), (13) | 15 hospitals in Beijing: emergency departments and respiratory wards | 1441 nurses, doctors and ward clerks; cluster randomization by hospital |
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Intervention 1: continual use, fit-tested N95 respirator Intervention 2: continual use, non–fit-tested N95 respirator Control: continual use, surgical mask
| Detection of influenza A and B, respiratory syncytial virus metapneumovirus, parainfluenza virus, rhinovirus–enterovirus, coronavirus, adenovirus, Streptococcus pneumoniae, Bordetella pertussis, Chlamydophila pneumoniae, Mycoplasma pneumoniae and Haemophilus influenzae type B |
MacIntyre et al., 2013 (14) | 19 hospitals in Beijing: emergency departments and respiratory wards | 1669 nurses, doctors and ward clerks; cluster randomization by ward |
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Intervention 1: continual use, fit-tested N95 respirator Intervention 2: targeted use, fit-tested N95 respirator Control: continual use, surgical mask
| Detection of influenza A and B, respiratory syncytial virus metapneumovirus, parainfluenza virus, rhinovirus–enterovirus, coronavirus, adenovirus, S. pneumoniae, B. pertussis, C. pneumoniae, M. pneumoniae and H. influenzae type B |
Cohort study |
Loeb et al., 2004 (15) | 2 hospitals in Ontario: coronary care units and ICUs with SARS patients | 43 nurses | Laboratory-confirmed respiratory infection |
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Case–control studies |
Seto et al., 2003 (16) | 5 hospitals in Hong Kong: emergency departments and medicine units | 13 infected (cases) and 241 noninfected (controls) nurses, doctors, health care assistants and domestic staff | Laboratory-confirmed respiratory infection |
N95 respirator Surgical mask Paper mask
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Zhang et al., 2013 (17) | 25 hospitals in Beijing: emergency departments, respiratory wards, ICUs, outpatient departments, technical clinic departments and management | 51 infected (cases) and 204 noninfected (controls) doctors, nurses, technicians and other | Laboratory-confirmed respiratory infection |
N95 respirator Surgical mask Cloth mask
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Cases and controls matched 1:4 by hospital, ward, age and sex 40 cases wore either N95 respirator or surgical mask 159 controls wore either surgical mask or N95 respirator Detection of pandemic H1N1 influenza virus
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