TABLE 5.

Negative SARS-CoV-2 air sampling studies in health care settings^a

Study settings	Design	Proportion of positive samples	Strengths (+) and limitations (−)
Cheng et al., 2020 ( 145) Hong Kong Low- and high-risk (including ICU)	6 pts in AIIR Air sampling: 50 liters/min for 20 min (1,000 liters), 10 cm from pts’ chin under an umbrella (air shelter)	Air: 0/6	(+) Increased proportion of exhaled air sampled under the umbrella (+) Sampling with and without mask-wearing (+) Detailed clinical data on pts
Faridi et al., 2020 ( 200) Iran Mostly high-risk (ICU)	44 hospitalized pts Air sampling: 1.5 liters/min for 1 h (90 liters) in shared pt rooms	Air: 0/10	(+) Detailed information on environment and interventions (−) Lack of clinical data on individual pts (−) Small volume of air sampled
Li et al., 2020 ( 201) Wuhan, China Low- and high-risk (including ICU)	Designated COVID-19 hospital with 800 severe cases (20 in ICU) Air sampling: 80 liters/min for 30 min (2,400 liters) in 45 areas (low, medium, and high risk)	Air: 0/135	(+) Three replicate samples at each location on separate days (−) 4-time-daily air disinfection (false negative) (−) Qualitative reverse transcriptase PCR
Wu et al., 2020 ( 147) Wuhan, China Low- and high-risk (including ICU)	Designated COVID-19 hospital Sampling in moderate-risk (buffer room for doffing) and high-risk (pt room) areas	Air: 0/44	(−) No description of pts (−) Unknown air sampling method (−) Open windows and UV light disinfection (potential false negatives)

^aAIIR, airborne infection isolation rooms; ICU, intensive care unit; pt(s), patient(s); Sx, symptom(s).