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. 2021 Feb 26;22(1):73.
doi: 10.1186/s12931-021-01637-8.

Characterization of hospital airborne SARS-CoV-2

Rebecca A Stern  1 , Petros Koutrakis  2 , Marco A G Martins  2 , Bernardo Lemos  3 , Scot E Dowd  4 , Elsie M Sunderland  1   2 , Eric Garshick  5   6   7
Affiliations

Characterization of hospital airborne SARS-CoV-2

Rebecca A Stern et al. Respir Res. .

Abstract

Background: The mechanism for spread of SARS-CoV-2 has been attributed to large particles produced by coughing and sneezing. There is controversy whether smaller airborne particles may transport SARS-CoV-2. Smaller particles, particularly fine particulate matter (≤ 2.5 µm in diameter), can remain airborne for longer periods than larger particles and after inhalation will penetrate deeply into the lungs. Little is known about the size distribution and location of airborne SARS-CoV-2 RNA.

Methods: As a measure of hospital-related exposure, air samples of three particle sizes (> 10.0 µm, 10.0-2.5 µm, and ≤ 2.5 µm) were collected in a Boston, Massachusetts (USA) hospital from April to May 2020 (N = 90 size-fractionated samples). Locations included outside negative-pressure COVID-19 wards, a hospital ward not directly involved in COVID-19 patient care, and the emergency department.

Results: SARS-CoV-2 RNA was present in 9% of samples and in all size fractions at concentrations of 5 to 51 copies m-3. Locations outside COVID-19 wards had the fewest positive samples. A non-COVID-19 ward had the highest number of positive samples, likely reflecting staff congregation. The probability of a positive sample was positively associated (r = 0.95, p < 0.01) with the number of COVID-19 patients in the hospital. The number of COVID-19 patients in the hospital was positively associated (r = 0.99, p < 0.01) with the number of new daily cases in Massachusetts.

Conclusions: More frequent detection of positive samples in non-COVID-19 than COVID-19 hospital areas indicates effectiveness of COVID-ward hospital controls in controlling air concentrations and suggests the potential for disease spread in areas without the strictest precautions. The positive associations regarding the probability of a positive sample, COVID-19 cases in the hospital, and cases in Massachusetts suggests that hospital air sample positivity was related to community burden. SARS-CoV-2 RNA with fine particulate matter supports the possibility of airborne transmission over distances greater than six feet. The findings support guidelines that limit exposure to airborne particles including fine particles capable of longer distance transport and greater lung penetration.

Keywords: Aerosol; COVID-19; Particulate matter; SARS-CoV-2; Size fraction.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Micro-environmental cascade impactor designed and custom-built by the Environmental Chemistry Laboratory at the Harvard T.H. Chan School of Public Health (HSPH). PUF polyurethane foam
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References

    1. Park S, Kim Y, Yi S, Lee S, Na B-J, Kim CB, Kim J, et al. Coronavirus disease outbreak in call center, South Korea. Emerg Infect Dis. 2020;26(8):1666. doi: 10.3201/eid2608.201274. - DOI - PMC - PubMed
    1. Hamner L, Dubbel P, Capron I. High SARS-CoV-2 attack rate following exposure at a choir practice—Skagit County, Washington, March 2020. MMWR Morb Mortal Wkly Rep. 2020;69:606–610. doi: 10.15585/mmwr.mm6919e6. - DOI - PubMed
    1. Morawska L, Cao J. Airborne transmission of SARS-CoV-2: the world should face the reality. Environ Int. 2020;139(April):105730. doi: 10.1016/j.envint.2020.105730. - DOI - PMC - PubMed
    1. Wang J, Du G. COVID-19 may transmit through aerosol. Ir J Med Sci. 2020;5:5–6. - PMC - PubMed
    1. Fineberg H. Rapid expert consultation on the possibility of bioaerosol spread of SARS-CoV-2 for the COVID-19 pandemic. In: The National Academies Press NRC, ed Washington, DC: The National Academies Press, National Research Council 2020.