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

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1 Credit CME
Key Points

Question  What is the level of air contamination from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in different hospital areas, and what factors are associated with contamination?

Findings  In this systematic review of 24 studies, 17% of air sampled from close patient environments was positive for SARS-CoV-2 RNA, with viability of the virus found in 9% of cultures.

Meaning  In this study, air both 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.


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 Review  The 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 (≤1 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 × 103 copies/m3 (0.4 × 103 to 3.1 × 103 copies/m3) in clinical areas to 9.7 × 103 copies/m3 (5.1 × 103 to 14.3 × 103 copies/m3) 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 × 103 to 40 × 103 copies/m3 and 3.8 × 103 to 7.2 × 103 TCID50/m3), 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 Relevance  In 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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Article Information

Accepted for Publication: November 18, 2020.

Published: December 23, 2020. doi:10.1001/jamanetworkopen.2020.33232

Correction: This article was corrected on January 26, 2021, to fix an error in Figure 3.

Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2020 Birgand G et al. JAMA Network Open.

Corresponding Author: Gabriel Birgand, PhD, Centre Hospitalo-Universitaire de Nantes, 5 rue du Professeur Yves Boquien, 44093 Nantes, France (

Author Contributions: Dr Birgand had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Birgand, Peiffer-Smadja, Fournier, Lucet.

Acquisition, analysis, or interpretation of data: Birgand, Peiffer-Smadja, Fournier, Kerneis, Lescure.

Drafting of the manuscript: Birgand, Fournier, Lucet.

Critical revision of the manuscript for important intellectual content: Birgand, Peiffer-Smadja, Kerneis, Lescure.

Statistical analysis: Birgand.

Supervision: Lescure, Lucet.

Conflict of Interest Disclosures: Dr Kerneis reported receiving personal fees, grants, and nonfinancial support from bioMérieux, travel fees from Accelerate Diagnostics, and personal fees from MSD outside the submitted work. Dr Lescure reported receiving personal fees from bioMérieux, Gilead, and MSD outside the submitted work. No other disclosures were reported.

Funding/Support: The research was funded by the National Institute for Health Research Health Protection Research Unit in Healthcare Associated Infection and Antimicrobial Resistance at Imperial College London in partnership with Public Health England. The support of Economic and Social Research Council as part of the Antimicrobial Cross Council initiative supported by the 7 UK research councils and also the support of the Global Challenges Research Fund is gratefully acknowledged.

Role of the Funder/Sponsor: The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Disclaimer: The views expressed are those of the authors and not necessarily those of the National Health Service, the National Institute for Health Research, the Department of Health, or Public Health England.

Meeting Presentation: These results have been presented at the virtual ESCMID Conference on Coronavirus Disease (ECCVID); September 23, 2020.

Additional Contributions: Marta Castrica, MSc (Department of Health, Animal Science and Food Safety VESPA, University of Milan, UNIMI), and Laura Menchetti, MSc (Faculty of Veterinary Medicine, Università degli Studi di Perugia, UNIPG) assisted with data collection. They were not compensated for their time.

World Health Organisation. Transmission of SARS-CoV-2: implications for infection prevention precautions. Published online July 9, 2020. Accessed November 23, 2020.
Birgand  G , Mutters  NT , Otter  JA ,  et al.  Analysis of national and international guidelines on respiratory protection equipment for COVID-19 in healthcare settings.  medRxiv. Preprint published online April 29, 2020. doi:10.1101/2020.04.23.20077230
Ong  SWX , Tan  YK , Chia  PY ,  et al.  Air, surface environmental, and personal protective equipment contamination by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from a symptomatic patient.   JAMA. 2020;323(16):1610-1612. doi:10.1001/jama.2020.3227PubMedGoogle ScholarCrossref
Bourouiba  L .  Turbulent gas clouds and respiratory pathogen emissions: potential implications for reducing transmission of COVID-19.   JAMA. 2020;323(18):1837-1838. doi:10.1001/jama.2020.4756PubMedGoogle Scholar
Seto  WH .  Airborne transmission and precautions: facts and myths.   J Hosp Infect. 2015;89(4):225-228. doi:10.1016/j.jhin.2014.11.005PubMedGoogle ScholarCrossref
Morawska  L , Tang  JW , Bahnfleth  W ,  et al.  How can airborne transmission of COVID-19 indoors be minimised?   Environ Int. 2020;142:105832. doi:10.1016/j.envint.2020.105832PubMedGoogle Scholar
Chagla  Z , Hota  S , Khan  S , Mertz  D ; International Hospital and Community Epidemiology Group.  Airborne transmission of COVID-19.   Clin Infect Dis. 2020;ciaa1118. doi:10.1093/cid/ciaa1118PubMedGoogle Scholar
Faridi  S , Niazi  S , Sadeghi  K ,  et al.  A field indoor air measurement of SARS-CoV-2 in the patient rooms of the largest hospital in Iran.   Sci Total Environ. 2020;725:138401. doi:10.1016/j.scitotenv.2020.138401PubMedGoogle Scholar
Liu  Y , Ning  Z , Chen  Y ,  et al.  Aerodynamic analysis of SARS-CoV-2 in two Wuhan hospitals.   Nature. 2020;582(7813):557-560. doi:10.1038/s41586-020-2271-3PubMedGoogle ScholarCrossref
Li  YH , Fan  YZ , Jiang  L , Wang  HB .  Aerosol and environmental surface monitoring for SARS-CoV-2 RNA in a designated hospital for severe COVID-19 patients.   Epidemiol Infect. 2020;148:e154. doi:10.1017/S0950268820001570PubMedGoogle Scholar
Guo  Z-D , Wang  Z-Y , Zhang  S-F ,  et al.  Aerosol and surface distribution of severe acute respiratory syndrome coronavirus 2 in hospital wards, Wuhan, China, 2020.   Emerg Infect Dis. 2020;26(7):1583-1591. doi:10.3201/eid2607.200885PubMedGoogle ScholarCrossref
Santarpia  JL , Rivera  DN , Herrera  V ,  et al.  Aerosol and surface transmission potential of SARS-CoV-2.  medRxiv. Preprint published online June 3, 2020. doi:10.1101/2020.03.23.20039446
Santarpia  JL , Herrera  VL , Rivera  DN ,  et al.  The infectious nature of patient-generated SARS-CoV-2 aerosol.  medRxiv. Preprint published online July 21, 2020. doi:10.1101/2020.07.13.20041632
Cheng  VC-C , Wong  S-C , Chan  VW-M ,  et al.  Air and environmental sampling for SARS-CoV-2 around hospitalized patients with coronavirus disease 2019 (COVID-19).   Infect Control Hosp Epidemiol. 2020;41(11):1258-1265. doi:10.1017/ice.2020.282PubMedGoogle ScholarCrossref
Wei  L , Lin  J , Duan  X ,  et al.  Asymptomatic COVID-19 patients can contaminate their surroundings: an environment sampling study.   mSphere. 2020;5(3):e00442-20. doi:10.1128/mSphere.00442-20PubMedGoogle Scholar
Chia  PY , Coleman  KK , Tan  YK ,  et al.  Detection of air and surface contamination by SARS-CoV-2 in hospital rooms of infected patients.   Nature Communications. 2020;11:2800. doi:10.1038/s41467-020-16670-2Google ScholarCrossref
Zhou  J , Otter  JA , Price  JR ,  et al.  Investigating SARS-CoV-2 surface and air contamination in an acute healthcare setting during the peak of the COVID-19 pandemic in London.   Clin Infect Dis. 2020;ciaa905. doi:10.1093/cid/ciaa905PubMedGoogle Scholar
Ding  Z , Qian  H , Xu  B ,  et al.  Toilets dominate environmental detection of SARS-CoV-2 virus in a hospital.  medRxiv. Preprint published online April 7, 2020. doi:10.1101/2020.04.03.20052175
Zhou  L , Yao  M , Zhang  X ,  et al.  Detection of SARS-CoV-2 in exhaled breath from COVID-19 patients ready for hospital discharge.  medRxiv. Preprint published online June 2, 2020. doi:10.1101/2020.05.31.20115196
Wu  S , Wang  Y , Jin  X , Tian  J , Liu  J , Mao  Y .  Environmental contamination by SARS-CoV-2 in a designated hospital for coronavirus disease 2019.   Am J Infect Control. 2020;48(8):910-914. doi:10.1016/j.ajic.2020.05.003PubMedGoogle ScholarCrossref
Cheng  VCC , Wong  S-C , Chen  JHK ,  et al.  Escalating infection control response to the rapidly evolving epidemiology of the coronavirus disease 2019 (COVID-19) due to SARS-CoV-2 in Hong Kong.   Infect Control Hosp Epidemiol. 2020;41(5):493-498. doi:10.1017/ice.2020.58PubMedGoogle ScholarCrossref
Lei  H , Ye  F , Liu  X ,  et al.  SARS-CoV-2 environmental contamination associated with persistently infected COVID-19 patients.   Influenza Other Respir Viruses. 2020;14(6):688-699. doi:10.1111/irv.12783PubMedGoogle ScholarCrossref
Razzini  K , Castrica  M , Menchetti  L ,  et al.  SARS-CoV-2 RNA detection in the air and on surfaces in the COVID-19 ward of a hospital in Milan, Italy.   Sci Total Environ. 2020;742:140540. doi:10.1016/j.scitotenv.2020.140540PubMedGoogle Scholar
Kim  UJ , Lee  SY , Lee  JY ,  et al.  Air and environmental contamination caused by COVID-19 patients: a multi-center study.   J Korean Med Sci. 2020;35(37):e332. doi:10.3346/jkms.2020.35.e332PubMedGoogle Scholar
Tan  L , Ma  B , Lai  X ,  et al.  Air and surface contamination by SARS-CoV-2 virus in a tertiary hospital in Wuhan, China.   Int J Infect Dis. 2020;99:3-7. doi:10.1016/j.ijid.2020.07.027PubMedGoogle ScholarCrossref
Binder  RA , Alarja  NA , Robie  ER ,  et al.  Environmental and aerosolized severe acute respiratory syndrome coronavirus 2 among hospitalized coronavirus disease 2019 patients.   J Infect Dis. 2020;222(11):1798-1806. doi:10.1093/infdis/jiaa575PubMedGoogle Scholar
Ahn  JY , An  S , Sohn  Y ,  et al.  Environmental contamination in the isolation rooms of COVID-19 patients with severe pneumonia requiring mechanical ventilation or high-flow oxygen therapy.   J Hosp Infect. 2020;106(3):570-576. doi:10.1016/j.jhin.2020.08.014PubMedGoogle ScholarCrossref
Kenarkoohi  A , Noorimotlagh  Z , Falahi  S ,  et al.  Hospital indoor air quality monitoring for the detection of SARS-CoV-2 (COVID-19) virus.   Sci Total Environ. 2020;748:141324. doi:10.1016/j.scitotenv.2020.141324PubMedGoogle Scholar
Jin  T , Li  J , Yang  J ,  et al.  SARS-CoV-2 presented in the air of an intensive care unit (ICU).   Sustain Cities Soc. 2020;102446. doi:10.1016/j.scs.2020.102446PubMedGoogle Scholar
Lednicky  JA , Lauzardo  M , Fan  ZH ,  et al.  Viable SARS-CoV-2 in the air of a hospital room with COVID-19 patients.   Int J Infect Dis. 2020;100:476-482. doi:10.1016/j.ijid.2020.09.025PubMedGoogle ScholarCrossref
Lui  RN , Wong  SH , Sánchez-Luna  SA ,  et al.  Overview of guidance for endoscopy during the coronavirus disease 2019 pandemic.   J Gastroenterol Hepatol. 2020;35(5):749-759. doi:10.1111/jgh.15053PubMedGoogle ScholarCrossref
Liu  Y , Yan  L-M , Wan  L ,  et al.  Viral dynamics in mild and severe cases of COVID-19.   Lancet Infect Dis. 2020;20(6):656-657. doi:10.1016/S1473-3099(20)30232-2PubMedGoogle ScholarCrossref
Wölfel  R , Corman  VM , Guggemos  W ,  et al.  Virological assessment of hospitalized patients with COVID-2019.   Nature. 2020;581(7809):465-469. doi:10.1038/s41586-020-2196-xPubMedGoogle ScholarCrossref
Tang  S , Mao  Y , Jones  RM ,  et al.  Aerosol transmission of SARS-CoV-2? evidence, prevention and control.   Environ Int. 2020;144:106039. doi:10.1016/j.envint.2020.106039PubMedGoogle Scholar
Singanayagam  A , Patel  M , Charlett  A ,  et al.  Duration of infectiousness and correlation with RT-PCR cycle threshold values in cases of COVID-19, England, January to May 2020.   Euro Surveill. 2020;25(32). doi:10.2807/1560-7917.ES.2020.25.32.2001483PubMedGoogle Scholar
Verreault  D , Moineau  S , Duchaine  C .  Methods for sampling of airborne viruses.   Microbiol Mol Biol Rev. 2008;72(3):413-444. doi:10.1128/MMBR.00002-08PubMedGoogle ScholarCrossref
Wang  W , Xu  Y , Gao  R ,  et al.  Detection of SARS-CoV-2 in different types of clinical specimens.   JAMA. 2020;323(18):1843-1844. doi:10.1001/jama.2020.3786PubMedGoogle Scholar
Wu  Y , Guo  C , Tang  L ,  et al.  Prolonged presence of SARS-CoV-2 viral RNA in faecal samples.   Lancet Gastroenterol Hepatol. 2020;5(5):434-435. doi:10.1016/S2468-1253(20)30083-2PubMedGoogle ScholarCrossref
Roy  CJ , Milton  DK .  Airborne transmission of communicable infection—the elusive pathway.   N Engl J Med. 2004;350(17):1710-1712. doi:10.1056/NEJMp048051PubMedGoogle ScholarCrossref
Booth  TF , Kournikakis  B , Bastien  N ,  et al.  Detection of airborne severe acute respiratory syndrome (SARS) coronavirus and environmental contamination in SARS outbreak units.   J Infect Dis. 2005;191(9):1472-1477. doi:10.1086/429634PubMedGoogle ScholarCrossref
Shiu  EYC , Leung  NHL , Cowling  BJ .  Controversy around airborne versus droplet transmission of respiratory viruses: implication for infection prevention.   Curr Opin Infect Dis. 2019;32(4):372-379. doi:10.1097/QCO.0000000000000563PubMedGoogle ScholarCrossref
Temkin  E ; Healthcare Worker COVID-19 Surveillance Working Group.  Extremely low prevalence of asymptomatic COVID-19 among healthcare workers caring for COVID-19 patients in Israeli hospitals: a cross-sectional study.   Clin Microbiol Infect. 2020;S1198-743X(20)30593-0. doi:10.1016/j.cmi.2020.09.040PubMedGoogle Scholar
Seto  WH , Tsang  D , Yung  RWH ,  et al; Advisors of Expert SARS group of Hospital Authority.  Effectiveness of precautions against droplets and contact in prevention of nosocomial transmission of severe acute respiratory syndrome (SARS).   Lancet. 2003;361(9368):1519-1520. doi:10.1016/S0140-6736(03)13168-6PubMedGoogle ScholarCrossref
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