Lack of viable severe acute respiratory coronavirus virus 2 (SARS-CoV-2) among PCR-positive air samples from hospital rooms and community isolation facilities

Ong, Sean Wei Xiang; Tan, Yian Kim; Coleman, Kristen K.; Tan, Boon Huan; Leo, Yee Sin; Wang, Dong Ling; Ng, Ching Ging; Ng, Oon Tek; Wong, Michelle; Marimuthu, Kalisvar

doi:10.1017/ice.2021.8

Cited by 32 publications

(27 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Information regarding the size fractionations of particles in the aerosols were provided by data generated using the PCIS and NIOSH bioaerosol sampler, which showed the virus-associated particles were >0.25 μm and >0.1 μm respectively. This is consistent with the findings of previous studies on the collection of airborne SARS-CoV-2 in different settings ( Chia et al, 2020 ; Feng et al, 2021 ; Lednicky, Lauzardo, et al, 2021 ; Liu et al, 2020b ; Ong et al, 2021 ). In general, particles in the respirable size range, i.e., particles of size <4 μm can reach the alveoli upon inhalation ( Brown et al, 2013 ).…”

Section: Discussionsupporting

confidence: 93%

SARS-CoV-2 in residential rooms of two self-isolating persons with COVID-19

Shankar

Witanachchi

Morea

et al. 2022

Journal of Aerosol Science

View full text Add to dashboard Cite

Individuals with COVID-19 are advised to self-isolate at their residences unless they require hospitalization. Persons sharing a dwelling with someone who has COVID-19 have a substantial risk of being exposed to the virus. However, environmental monitoring for the detection of virus in such settings is limited. We present a pilot study on environmental sampling for SARS-CoV-2 virions in the residential rooms of two volunteers with COVID-19 who self-quarantined. Apart from standard surface swab sampling, based on availability, four air samplers positioned 0.3–2.2 m from the volunteers were used: a VI able V irus A erosol S ampler (VIVAS), an inline air sampler that traps particles on polytetrafluoroethylene (PTFE) filters, a NIOSH 2-stage cyclone sampler (BC-251), and a Sioutas personal cascade impactor sampler (PCIS). The latter two selectively collect particles of specific size ranges. SARS-CoV-2 RNA was detected by real-time Reverse-Transcription quantitative Polymerase Chain Reaction (rRT-qPCR) analyses of particles in one air sample from the room of volunteer A and in various air and surface samples from that of volunteer B. The one positive sample collected by the NIOSH sampler from volunteer A's room had a quantitation cycle (Cq) of 38.21 for the N-gene, indicating a low amount of airborne virus [5.69E-02 SARS-CoV-2 genome equivalents (GE)/cm 3 of air]. In contrast, air samples and surface samples collected off the mobile phone in volunteer B's room yielded Cq values ranging from 14.58 to 24.73 and 21.01 to 24.74, respectively, on the first day of sampling, indicating that this volunteer was actively shedding relatively high amounts of SARS-CoV-2 at that time. The SARS-CoV-2 GE/cm 3 of air for the air samples collected by the PCIS was in the range 6.84E+04 to 3.04E+05 using the LED-N primer system, the highest being from the stage 4 filter, and similarly, ranged from 2.54E+03 to 1.68E+05 GE/cm 3 in air collected by the NIOSH sampler. Attempts to isolate the virus in cell culture from the samples from volunteer B's room with the aforementioned Cq values were unsuccessful due to out-competition by a co-infecting Human adenovirus B3 (HAdVB3) that killed the Vero E6 cell cultures within 4 days of their inoculation, although Cq values of 34.56–37.32 were measured upon rRT-qPCR analyses of vRNA purified from the cell culture medium. The size distribution of SARS-CoV-2-laden aerosol particles collected from the air of volunteer B's room was >0.25 μm and >0.1 μm as recorded by the PCIS and the NIOSH sampler, respectively, suggesting a risk of aerosol transmission since these particles can remain suspended in air for an extended time and travel over long distances. The detection of virus in surface samples also underscores the potential for fomite transmission of SARS-CoV-2 in indoor settings.

show abstract

Section: Discussionsupporting

confidence: 93%

SARS-CoV-2 in residential rooms of two self-isolating persons with COVID-19

Shankar

Witanachchi

Morea

et al. 2022

Journal of Aerosol Science

View full text Add to dashboard Cite

show abstract

“…While it has been previously shown that COVID-19 patients can emit infectious virus-laden aerosols into their environments [5,20], most environmental SARS-CoV-2 sampling studies have been unable to mechanically retrieve and isolate viable virus from ambient air in the vicinity of COVID-19 patients [21]. Hence, the infectious proportion of virus emitted from patient expiration remains unclear.…”

Section: Discussionmentioning

confidence: 99%

Viral Load of SARS-CoV-2 in Respiratory Aerosols Emitted by COVID-19 Patients while Breathing, Talking, and Singing

Coleman

Tay

Tan

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

Background: Multiple SARS-CoV-2 superspreading events suggest that aerosols play an important role in driving the COVID-19 pandemic. However, the detailed roles of coarse (>5μm) and fine (≤5μm) respiratory aerosols produced when breathing, talking, and singing are not well-understood. Methods: Using a G-II exhaled breath collector, we measured viral RNA in coarse and fine respiratory aerosols emitted by COVID-19 patients during 30 minutes of breathing, 15 minutes of talking, and 15 minutes of singing. Results: Among the 22 study participants, 13 (59%) emitted detectable levels of SARS-CoV-2 RNA in respiratory aerosols, including 3 asymptomatic patients and 1 presymptomatic patient. Viral loads ranged from 63 - 5,821 N gene copies per expiratory activity. Patients earlier in illness were more likely to emit detectable RNA, and loads differed significantly between breathing, talking, and singing. The largest proportion of SARS-CoV-2 RNA copies was emitted by singing (53%), followed by talking (41%) and breathing (6%). Overall, fine aerosols constituted 85% of the viral load detected in our study. Virus cultures were negative. Conclusions: Fine aerosols produced by talking and singing contain more SARS-CoV-2 copies than coarse aerosols and may play a significant role in the transmission of SARS-CoV-2. Exposure to fine aerosols should be mitigated, especially in indoor environments where airborne transmission of SARS-CoV-2 is likely to occur. Isolating viable SARS-CoV-2 from respiratory aerosol samples remains challenging, and whether this can be more easily accomplished for emerging SARS-CoV-2 variants is an important enquiry for future studies.

show abstract

“…Our studies support reports of infectious SARS-CoV-2 collected from aerosols near COVID-19 patients [4][5][6][7], as well as studies showing non-contact transmission of SARS-CoV-2 between ferrets and hamsters [17,18,22], including one study that demonstrated transmission over a 1-meter distance [28]. Some previous studies have been unable to culture virus from air samples from COVID-19 patients or inoculated non-human primates due to unknown collection times post-onset of disease or the use of air sampling equipment or buffers that do not maintain viral infectivity [16,29]. Our results support the idea that transmission is likely to occur prior to or concurrent with symptom onset or in the absence of clinical disease, supporting studies that have found that asymptomatic infection is a major driver of community transmission [23,24].…”

Section: Discussionmentioning

confidence: 99%

Infectious SARS-CoV-2 is emitted in aerosols

Hawks

Prussin

Kuchinsky

et al. 2021

Preprint

View full text Add to dashboard Cite

Respiratory viruses such as SARS-CoV-2 are transmitted in respiratory droplets and aerosols, which are released during talking, breathing, coughing, and sneezing. Non-contact transmission of SARS-CoV-2 has been demonstrated, suggesting transmission in aerosols. Here we demonstrate that golden Syrian hamsters emit infectious SARS-CoV-2 in aerosols, prior to and concurrent with the onset of mild clinical signs of disease. The emission rate is 25 infectious virions/hour on days 1 and 2 post-inoculation, with viral RNA levels 200-fold higher than infectious virus in aerosols. Female hamsters have delayed kinetics of viral shedding in aerosols compared to male hamsters. The majority of virus is contained within aerosols <8 microns in size. Thus, we provide direct evidence that, in hamsters, SARS-CoV-2 is an airborne virus.

show abstract

Lack of viable severe acute respiratory coronavirus virus 2 (SARS-CoV-2) among PCR-positive air samples from hospital rooms and community isolation facilities

Cited by 32 publications

References 26 publications

SARS-CoV-2 in residential rooms of two self-isolating persons with COVID-19

SARS-CoV-2 in residential rooms of two self-isolating persons with COVID-19

Viral Load of SARS-CoV-2 in Respiratory Aerosols Emitted by COVID-19 Patients while Breathing, Talking, and Singing

Infectious SARS-CoV-2 is emitted in aerosols

Contact Info

Product

Resources

About