Airborne or droplet? That is the question. This paper is quite concerning. Spoiler alert: they recommend the use of airborne isolation precautions.
n=13 confirmed COVID patients.
Some of these patients were hospitalized (NBU unit) and some of these patients were quarantined (NQU) either asymptomatic or with mild symptoms.
They did the best they could to contain the virus regarding PPE, negative pressure, and the like.
They obtained a total of 163 surface and air samples in these rooms combined. Those samples were analyzed by PCR methods.
77.3% of those samples were positive for SARS-CoV-2.
76.5% of all personal items were positive.
- Cell phones: 83.3% positive
- Toilets: 81% positive
- Remote controls: 64.7% positive
- Bedside tables and rails: 75% positive
- Window ledges (how did it get over there?!!?): 81.8% positive
Here's the kicker, though
- Room air samples: 63.2% positive
- They stated a case where the sampler was greater than 6ft away from a patient who was on 1L NC and the sample was positive for COVID-19.
- The highest airborne concentrations noted on patients receiving nasal cannula. They mentioned that these patients hadn't coughed. Again, they were not looking at any other modality of oxygenation.
- 66.7% of HALLWAY air samples had virus-containing particles. People going in and out of the rooms were carrying the airborne virus.
We are in deep poop, team.
I know the CDC and WHO are saying something different but that can they provide a similar study to this? Crickets.
-EJ
Link to Abstract
Link to FULL FREE Article
Although great care has been taken to ensure that the information in this post is accurate, eddyjoemd, LLC shall not be held responsible or in any way liable for the continued accuracy of the information, or for any errors, omissions or inaccuracies, or for any consequences arising therefrom.
ADDENDUM: The World Health Organization has obtained the paper I referenced above as well as the study in the NEJM that I covered on 3/18/2020. Please read the document for yourself. I have provided links, as always. Please interpret this data yourself. Don't trust me.
Regarding the NEJM study which concluded that the virus could be in the air up to three hours:
Their take: "the finding of COVID-19 virus in aerosol particles up to 3 hours does not reflect a clinical setting in which aerosol-generating procedures are performed—that is, this was an experimentally induced aerosol-generating procedure."
My take: okay then, can you please give us some data as to how long we could expect it during clinical settings of aerosol-generating procedures to be in the room? Can we have some expert guidance?
Regarding the study I posted yesterday, 3/30.
The WHO provided citations for two studies, one published in JAMA (Ong study) and the other in Infection Control and Hospital Epidemiology to disprove the Santarpia study.
Their take: "It is important to note that the detection of RNA in environmental samples based on PCR-based assays is not indicative of viable virus that could be transmissible. Further studies are needed to determine whether it is possible to detect COVID-19 virus in air samples from patient rooms where no procedures or support treatments that generate aerosols are ongoing. As evidence emerges, it is important to know whether viable virus is found and what role it may play in transmission."
My take: since we don't know with reasonable certainty, then we should err on the side of caution and protect our teams.
Here are the two studies cited by WHO as to why it is NOT airborne.
Ong study: sampled 3 patients, the one who was the sickest noted the virus in the air outlet fans (airborne infection isolation rooms). Per the article, this suggests "that small virus-laden droplets may be displaced by airflows and deposited on equipment such as vents". The limitation stated by the authors includes that "the volume of air sampled represents only a small fraction of total volume, and air exchanges in the room would have diluted the presence of SARS-CoV-2 in the air. Further studies are required to confirm these preliminary results." In this study they also found the virus on the shoe of a physician.
My take: Hardly concrete not definitive.
Cheng study: "air samples were all undetectable for SARS-CoV-2 RNA when the patients were performing 4 different maneuvers (normal breathing, deep breathing, speaking 1, 2, and 3 continuously, and coughing continuously) while putting on and putting off the surgical mask."
It seems based on the discussion that they did this on only ONE patient. They state "we may not be able to make a definite conclusion based on the analysis of a single patient".
My take: inconclusive.
My understanding is that a viral culture is needed to assess viability rather than PCR. Neither of these studies looked at viral cultures. WHO, can you get this for us?
Citations:
WHO Commentary on Transmission Modalities
Cheng V, Wong S-C, Chen J, Yip C, Chuang V, Tsang O, 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 Mar 5 [Epub ahead of print].
Link to Abstract
Their take: "the finding of COVID-19 virus in aerosol particles up to 3 hours does not reflect a clinical setting in which aerosol-generating procedures are performed—that is, this was an experimentally induced aerosol-generating procedure."
My take: okay then, can you please give us some data as to how long we could expect it during clinical settings of aerosol-generating procedures to be in the room? Can we have some expert guidance?
Regarding the study I posted yesterday, 3/30.
The WHO provided citations for two studies, one published in JAMA (Ong study) and the other in Infection Control and Hospital Epidemiology to disprove the Santarpia study.
Their take: "It is important to note that the detection of RNA in environmental samples based on PCR-based assays is not indicative of viable virus that could be transmissible. Further studies are needed to determine whether it is possible to detect COVID-19 virus in air samples from patient rooms where no procedures or support treatments that generate aerosols are ongoing. As evidence emerges, it is important to know whether viable virus is found and what role it may play in transmission."
My take: since we don't know with reasonable certainty, then we should err on the side of caution and protect our teams.
Here are the two studies cited by WHO as to why it is NOT airborne.
Ong study: sampled 3 patients, the one who was the sickest noted the virus in the air outlet fans (airborne infection isolation rooms). Per the article, this suggests "that small virus-laden droplets may be displaced by airflows and deposited on equipment such as vents". The limitation stated by the authors includes that "the volume of air sampled represents only a small fraction of total volume, and air exchanges in the room would have diluted the presence of SARS-CoV-2 in the air. Further studies are required to confirm these preliminary results." In this study they also found the virus on the shoe of a physician.
My take: Hardly concrete not definitive.
Cheng study: "air samples were all undetectable for SARS-CoV-2 RNA when the patients were performing 4 different maneuvers (normal breathing, deep breathing, speaking 1, 2, and 3 continuously, and coughing continuously) while putting on and putting off the surgical mask."
It seems based on the discussion that they did this on only ONE patient. They state "we may not be able to make a definite conclusion based on the analysis of a single patient".
My take: inconclusive.
My understanding is that a viral culture is needed to assess viability rather than PCR. Neither of these studies looked at viral cultures. WHO, can you get this for us?
Citations:
WHO Commentary on Transmission Modalities
Cheng V, Wong S-C, Chen J, Yip C, Chuang V, Tsang O, 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 Mar 5 [Epub ahead of print].
Link to Abstract
Link to FULL FREE PDF
Ong SW, Tan YK, Chia PY, Lee TH, Ng OT, Wong MS, 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
Link to FULL FREE Article
Although great care has been taken to ensure that the information in this post is accurate, eddyjoemd, LLC shall not be held responsible or in any way liable for the continued accuracy of the information, or for any errors, omissions or inaccuracies, or for any consequences arising therefrom.
Ong SW, Tan YK, Chia PY, Lee TH, Ng OT, Wong MS, 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
Link to FULL FREE Article
Although great care has been taken to ensure that the information in this post is accurate, eddyjoemd, LLC shall not be held responsible or in any way liable for the continued accuracy of the information, or for any errors, omissions or inaccuracies, or for any consequences arising therefrom.
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