Viable SARS-CoV-2 detected in the air of hospital rooms of patients with COVID-19 with an early infection.

Objectives: This study assessed the concentration of SARS-CoV-2 in the air of hospital rooms occupied by patients with COVID-19 who had viable SARS-CoV-2 in nasopharyngeal (NP) samples in early infection.

Methods: Between July and October 2021, NP swabs were collected from 20 patients with early SARS-CoV-2 infection admitted to a tertiary hospital in Japan. Air samples were collected from their rooms, tested for SARS-CoV-2 RNA, and cultured to determine potential infectivity.

Results: The NP swab samples of 18 patients were positive for viable SARS-CoV-2 (median concentration: 4.0 × 10 tissue culture infectious dose 50/ml). In the air samples, viral RNA (median concentration: 1.1 × 10 copies/m) was detected in 12/18 (67%) patients, and viable virus (median concentration: 8.9 × 10 tissue culture infectious dose 50/m) was detected in 5/18 (28%) patients. The median time between illness onset and sampling was 3 days. The RNA concentration was significantly higher in samples wherein viable SARS-CoV-2 was detected than in samples in which viable virus was not detected (P-value = 0.027).

Conclusion: Viable SARS-CoV-2 can be detected in the air surrounding patients with early SARS-CoV-2 infection. Health care workers should pay attention to infection control when caring for patients with early SARS-CoV-2 infection.