Tags

Type your tag names separated by a space and hit enter

Quantitative assessment of the risk of airborne transmission of SARS-CoV-2 infection: Prospective and retrospective applications.
Environ Int. 2020 12; 145:106112.EI

Abstract

Airborne transmission is a recognized pathway of contagion; however, it is rarely quantitatively evaluated. The numerous outbreaks that have occurred during the SARS-CoV-2 pandemic are putting a demand on researchers to develop approaches capable of both predicting contagion in closed environments (predictive assessment) and analyzing previous infections (retrospective assessment). This study presents a novel approach for quantitative assessment of the individual infection risk of susceptible subjects exposed in indoor microenvironments in the presence of an asymptomatic infected SARS-CoV-2 subject. The application of a Monte Carlo method allowed the risk for an exposed healthy subject to be evaluated or, starting from an acceptable risk, the maximum exposure time. We applied the proposed approach to four distinct scenarios for a prospective assessment, highlighting that, in order to guarantee an acceptable risk of 10-3 for exposed subjects in naturally ventilated indoor environments, the exposure time could be well below one hour. Such maximum exposure time clearly depends on the viral load emission of the infected subject and on the exposure conditions; thus, longer exposure times were estimated for mechanically ventilated indoor environments and lower viral load emissions. The proposed approach was used for retrospective assessment of documented outbreaks in a restaurant in Guangzhou (China) and at a choir rehearsal in Mount Vernon (USA), showing that, in both cases, the high attack rate values can be justified only assuming the airborne transmission as the main route of contagion. Moreover, we show that such outbreaks are not caused by the rare presence of a superspreader, but can be likely explained by the co-existence of conditions, including emission and exposure parameters, leading to a highly probable event, which can be defined as a "superspreading event".

Authors+Show Affiliations

Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, FR, Italy; International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Qld, Australia.International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Qld, Australia.Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, FR, Italy. Electronic address: l.stabile@unicas.it.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

32927282

Citation

Buonanno, G, et al. "Quantitative Assessment of the Risk of Airborne Transmission of SARS-CoV-2 Infection: Prospective and Retrospective Applications." Environment International, vol. 145, 2020, p. 106112.
Buonanno G, Morawska L, Stabile L. Quantitative assessment of the risk of airborne transmission of SARS-CoV-2 infection: Prospective and retrospective applications. Environ Int. 2020;145:106112.
Buonanno, G., Morawska, L., & Stabile, L. (2020). Quantitative assessment of the risk of airborne transmission of SARS-CoV-2 infection: Prospective and retrospective applications. Environment International, 145, 106112. https://doi.org/10.1016/j.envint.2020.106112
Buonanno G, Morawska L, Stabile L. Quantitative Assessment of the Risk of Airborne Transmission of SARS-CoV-2 Infection: Prospective and Retrospective Applications. Environ Int. 2020;145:106112. PubMed PMID: 32927282.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Quantitative assessment of the risk of airborne transmission of SARS-CoV-2 infection: Prospective and retrospective applications. AU - Buonanno,G, AU - Morawska,L, AU - Stabile,L, Y1 - 2020/09/06/ PY - 2020/06/08/received PY - 2020/07/28/revised PY - 2020/08/31/accepted PY - 2020/9/15/pubmed PY - 2020/10/28/medline PY - 2020/9/14/entrez KW - Coronavirus KW - Indoor KW - SARS-CoV-2 (COVID-19) assessment KW - Ventilation KW - Virus airborne transmission SP - 106112 EP - 106112 JF - Environment international JO - Environ Int VL - 145 N2 - Airborne transmission is a recognized pathway of contagion; however, it is rarely quantitatively evaluated. The numerous outbreaks that have occurred during the SARS-CoV-2 pandemic are putting a demand on researchers to develop approaches capable of both predicting contagion in closed environments (predictive assessment) and analyzing previous infections (retrospective assessment). This study presents a novel approach for quantitative assessment of the individual infection risk of susceptible subjects exposed in indoor microenvironments in the presence of an asymptomatic infected SARS-CoV-2 subject. The application of a Monte Carlo method allowed the risk for an exposed healthy subject to be evaluated or, starting from an acceptable risk, the maximum exposure time. We applied the proposed approach to four distinct scenarios for a prospective assessment, highlighting that, in order to guarantee an acceptable risk of 10-3 for exposed subjects in naturally ventilated indoor environments, the exposure time could be well below one hour. Such maximum exposure time clearly depends on the viral load emission of the infected subject and on the exposure conditions; thus, longer exposure times were estimated for mechanically ventilated indoor environments and lower viral load emissions. The proposed approach was used for retrospective assessment of documented outbreaks in a restaurant in Guangzhou (China) and at a choir rehearsal in Mount Vernon (USA), showing that, in both cases, the high attack rate values can be justified only assuming the airborne transmission as the main route of contagion. Moreover, we show that such outbreaks are not caused by the rare presence of a superspreader, but can be likely explained by the co-existence of conditions, including emission and exposure parameters, leading to a highly probable event, which can be defined as a "superspreading event". SN - 1873-6750 UR - https://www.unboundmedicine.com/medline/citation/32927282/Quantitative_assessment_of_the_risk_of_airborne_transmission_of_SARS_CoV_2_infection:_Prospective_and_retrospective_applications_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0160-4120(20)32067-5 DB - PRIME DP - Unbound Medicine ER -