Environmental and Aerosolized Severe Acute Respiratory Syndrome Coronavirus 2 Among Hospitalized Coronavirus Disease 2019 Patients

Binder, Raquel A.; Alarja, Natalie A; Robie, Emily R; Kochek, Kara; Xiu, Leshan; Rocha-Melogno, Lucas; Abdelgadir, Anfal; Goli, Sumana; Farrell, Amanda S.; Coleman, Kristen K.; Turner, Abigail L; Lautredou, Cassandra C; Lednicky, John A.; Lee, Mark J.; Polage, Christopher R.; Simmons, Ryan; Deshusses, Marc A.; Anderson, Benjamin D.; Gray, Gregory C.

doi:10.1093/infdis/jiaa575

Cited by 61 publications

(79 citation statements)

References 26 publications

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“…Indeed, a better understanding of viral resistance to airborne stress is key to estimating infectious risk. Three published studies (103)(104)(105) included viral cultures from air samples, all of which were negative; however, the Santarpia et al study (103) observed indirect signs of viral replication in two of their samples, including a mild cytopathic effect upon microscopic inspection after 3 to 4 days. On the other hand, in two unpublished studies, Santarpia Western blotting to yield interesting results.…”

Section: Air and No-touch Surface Samplingmentioning

confidence: 99%

SARS-CoV-2 and Health Care Worker Protection in Low-Risk Settings: a Review of Modes of Transmission and a Novel Airborne Model Involving Inhalable Particles

Zhang

Duchaine

2020

Clin Microbiol Rev

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SUMMARY Since the beginning of the COVID-19 pandemic, there has been intense debate over SARS-CoV-2’s mode of transmission and appropriate personal protective equipment for health care workers in low-risk settings. The objective of this review is to identify and appraise the available evidence (clinical trials and laboratory studies on masks and respirators, epidemiological studies, and air sampling studies), clarify key concepts and necessary conditions for airborne transmission, and shed light on knowledge gaps in the field. We find that, except for aerosol-generating procedures, the overall data in support of airborne transmission—taken in its traditional definition (long-distance and respirable aerosols)—are weak, based predominantly on indirect and experimental rather than clinical or epidemiological evidence. Consequently, we propose a revised and broader definition of “airborne,” going beyond the current droplet and aerosol dichotomy and involving short-range inhalable particles, supported by data targeting the nose as the main viral receptor site. This new model better explains clinical observations, especially in the context of close and prolonged contacts between health care workers and patients, and reconciles seemingly contradictory data in the SARS-CoV-2 literature. The model also carries important implications for personal protective equipment and environmental controls, such as ventilation, in health care settings. However, further studies, especially clinical trials, are needed to complete the picture.

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Section: Air and No-touch Surface Samplingmentioning

confidence: 99%

SARS-CoV-2 and Health Care Worker Protection in Low-Risk Settings: a Review of Modes of Transmission and a Novel Airborne Model Involving Inhalable Particles

Zhang

Duchaine

2020

Clin Microbiol Rev

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“…After further screening and supplementary searching of articles published or posted between January 1 and October 27, 2020, we identified an additional article, and a total of 24 articles were included in the review ( Figure 1 ). 3 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 …”

Section: Resultsmentioning

confidence: 99%

“…Of the 24 included studies, all were cross-sectional observational studies. Ten studies (41.7%) were from China, [9][10][11]15,[18][19][20]22,25,29 and the remaining were from the United States (4 [16.7%]), 12,13,26,30 Hong Kong (2 [8.3%]), 14,21 Korea (2 [8.3%]), 24,27 Singapore (2 [8.3%]), 3,16 Iran (2 [8.3%]), 8,28 the United Kingdom (1 [4.2%]), 19 and Italy (1 [4.2%]). 23 Of all included articles and studies, 20…”

Section: Characteristics Of Included Articles and Studiesmentioning

confidence: 99%

“…(83.3%) 3,[8][9][10][11][14][15][16][17][20][21][22][23][24][25][26][27][28][29][30] were published in peer-reviewed journals, and 4 (16.7%) 12,13,17,18 were posted on preprint servers.…”

Section: Characteristics Of Included Articles and Studiesmentioning

confidence: 99%

“…The viral culture was planned in the methods of 6 studies (20.8%) 12,13,17,26,27,30 but performed in 5 (12.5%) of them. 12,13,17,26,30 The remaining did not perform viral culture due to negative RT-PCR results. Three studies (12.5%) 9,13,16 assessed the particle size in parallel to RNA concentration or viral titer.…”

Section: Characteristics Of Included Articles and Studiesmentioning

confidence: 99%

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Assessment of Air Contamination by SARS-CoV-2 in Hospital Settings

et al. 2020

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IMPORTANCE Controversy remains regarding the transmission routes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).OBJECTIVE To review current evidence on air contamination with SARS-CoV-2 in hospital settings and the factors associated with contamination, including viral load and particle size. EVIDENCE REVIEWThe MEDLINE, Embase, and Web of Science databases were systematically queried for original English-language articles detailing SARS-CoV-2 air contamination in hospital settings between January 1 and October 27, 2020. This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. The positivity rate of SARS-CoV-2 viral RNA and culture were described and compared according to the setting, clinical context, air ventilation system, and distance from patients. The SARS-CoV-2 RNA concentrations in copies per meter cubed of air were pooled, and their distribution was described by hospital areas. Particle sizes and SARS-CoV-2 RNA concentrations in copies or median tissue culture infectious dose (TCID50) per meter cubed were analyzed after categorization as less than 1 μm, from 1 to 4 μm, and greater than 4 μm. FINDINGS Among 2284 records identified, 24 cross-sectional observational studies were included in the review. Overall, 82 of 471 air samples (17.4%) from close patient environments were positive for SARS-CoV-2 RNA, with a significantly higher positivity rate in intensive care unit settings (intensive care unit, 27 of 107 [25.2%] vs non-intensive care unit, 39 of 364 [10.7%]; P < .001). There was no difference according to the distance from patients (Յ1 m, 3 of 118 [2.5%] vs >1-5 m, 13 of 236 [5.5%]; P = .22). The positivity rate was 5 of 21 air samples (23.8%) in toilets, 20 of 242 (8.3%) in clinical areas, 15 of 122 (12.3%) in staff areas, and 14 of 42 (33.3%) in public areas. A total of 81 viral cultures were performed across 5 studies, and 7 (8.6%) from 2 studies were positive, all from close patient environments. The median (interquartile range) SARS-CoV-2 RNA concentrations varied from 1.0 × 10 3 copies/m 3 (0.4 × 10 3 to 3.1 × 10 3 copies/m 3 ) in clinical areas to 9.7 × 10 3 copies/m 3 (5.1 × 10 3 to 14.3 × 10 3 copies/m 3 ) in the air of toilets or bathrooms. Protective equipment removal and patient rooms had high concentrations per titer of SARS-CoV-2 (varying from 0.9 × 10 3 to 40 × 10 3 copies/m 3 and 3.8 × 10 3 to 7.2 × 10 3 TCID50/m 3 ), with aerosol size distributions that showed peaks in the region of particle size less than 1 μm; staff offices had peaks in the region of particle size greater than 4 μm. CONCLUSIONS AND RELEVANCEIn this systematic review, the air close to and distant from patients with coronavirus disease 2019 was frequently contaminated with SARS-CoV-2 RNA; however, few of these samples contained viable viruses. High viral loads found in toilets and bathrooms, staff areas, and public hallways suggest that these areas should be carefully considered.

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Assessing severe acute respiratory syndrome coronavirus 2 infectivity by reverse‐transcription polymerase chain reaction: A systematic review and meta‐analysis

Fomenko

Weibel

Moezi

et al. 2022

Reviews in Medical Virology

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The cornerstone of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) detection is reverse‐transcription polymerase chain reaction (RT‐PCR) of viral RNA. As a surrogate assay SARS‐CoV‐2 RNA detection does not necessarily imply infectivity. Only virus isolation in permissive cell culture systems can indicate infectivity. Here, we review the evidence on RT‐PCR performance in detecting infectious SARS‐CoV‐2. We searched for any studies that used RT‐PCR and cell culture to determine infectious SARS‐CoV‐2 in respiratory samples. We assessed (i) diagnostic accuracy of RT‐PCR compared to cell culture as reference test, (ii) performed meta‐analysis of positive predictive values (PPV) and (iii) determined the virus isolation probabilities depending on cycle threshold (Ct) or log 10 genome copies/ml using logistic regression. We included 55 studies. There is substantial statistical and clinical heterogeneity. Seven studies were included for diagnostic accuracy. Sensitivity ranged from 90% to 99% and specificity from 29% to 92%. In meta‐analysis, the PPVs varied across subgroups with different sampling times after symptom onset, with 1% (95% confidence interval [CI], 0%–7%) in sampling beyond 10 days and 27% (CI, 19%–36%) to 46% (CI, 33%–60%) in subgroups that also included earlier samples. Estimates of virus isolation probability varied between 6% (CI, 0%–100%) and 50% (CI, 0%–100%) at a Ct value of 30 and between 0% (CI, 0%–22%) and 63% (CI, 0%–100%) at 5 log 10 genome copies/ml. Evidence on RT‐PCR performance in detecting infectious SARS‐CoV‐2 in respiratory samples was limited. Major limitations were heterogeneity and poor reporting. RT‐PCR and cell culture protocols need further standardisation.

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Environmental and Aerosolized Severe Acute Respiratory Syndrome Coronavirus 2 Among Hospitalized Coronavirus Disease 2019 Patients

Cited by 61 publications

References 26 publications

SARS-CoV-2 and Health Care Worker Protection in Low-Risk Settings: a Review of Modes of Transmission and a Novel Airborne Model Involving Inhalable Particles

SARS-CoV-2 and Health Care Worker Protection in Low-Risk Settings: a Review of Modes of Transmission and a Novel Airborne Model Involving Inhalable Particles

Assessment of Air Contamination by SARS-CoV-2 in Hospital Settings

Assessing severe acute respiratory syndrome coronavirus 2 infectivity by reverse‐transcription polymerase chain reaction: A systematic review and meta‐analysis

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