Table 4.

 Synopsis of an observational cohort study evaluating mask and respirator use for SARS

Author/country (reference)	Study design and participants	Reported results	Comments
Loeb/Canada (18)	Retrospective cohort of 43 nurses who worked in ICU or CCU when laboratory‐confirmed SARS patient in unit; analysis limited to 32 nurses who entered patient’s room at least once.	3 (13%) of 23 nurses who consistently wore mask (either surgical or N95 respirator) developed SARS compared with 5 (56%) of 9 nurses who did not consistently wear either (RR 0·23, P = 0·02). 2 (13%) of 16 nurses who consistently wore N95 respirator developed SARS compared with 1 (25%) of 4 nurses who consistently wore a surgical mask (RR = 0·50, P = 0·51).	Underpowered study; recall bias possible; community exposure not explored; no serological testing of controls.

SARS, severe acute respiratory syndrome; PPE, personal protective equipment; ILI, influenza‐like illness; ICU, intensive care unit; CCU, coronary care unit.