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7305693 
Journal Article 
Lack of viable SARS-CoV-2 among PCR-positive air samples from hospital rooms and community isolation facilities 
Ong, SWX; Tan, YK; Coleman, KK; Tan, BH; Leo, YS; Wang, DL; Ng, CG; Ng, OT; Wong, MSY; Marimuthu, K 
2021 
Yes 
Infection Control and Hospital Epidemiology
ISSN: 0899-823X
EISSN: 1559-6834 
1-17 
English 
33487210 
BACKGROUND: Understanding the extent of aerosol-based transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is important to tailor interventions for control of the coronavirus disease 2019 (COVID-19) pandemic. Multiple studies have reported the detection of SARS-CoV-2 nucleic acid in air samples but only one has successfully recovered viable virus, though this is limited by small sample size. We aimed to determine the extent of shedding of viable SARS-CoV-2 in respiratory aerosols from COVID-19 patients.

METHODS: In this observational air sampling study, air samples from airborne infection isolation rooms (AIIRs) and a community isolation facility (CIF) housing COVID-19 patients were collected using a water vapor condensation method into liquid collection media. Samples were tested for presence of SARS-CoV-2 nucleic acid using quantitative real-time polymerase chain reaction (qRT-PCR), and qRT-PCR-positive samples were tested for viability using viral culture.

RESULTS: Samples from six (50%) of the 12 sampling cycles in hospital rooms were positive for SARS-CoV-2 RNA, including aerosols ranging from <1 µm to >4 µm in diameter. One sample of nine from the CIF was positive via qRT-PCR. Viral RNA concentrations range from 179 to 2738 ORF1ab gene copies m-3 air. Virus cultures were negative after four blind passages.

CONCLUSION: While SARS-CoV-2 is readily captured in aerosols, virus culture remains challenging despite optimized sampling methodologies to preserve virus viability. Further studies on aerosol-based transmission and control of SARS-CoV-2 are needed while we await safe and effective vaccines.