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Online Discussion: Tracking new emerging diseases and the next pandemic; Coronavirus Pandemic Discussion Forum.

SARS-CoV-2 Environmental Survival

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Tabitha111 View Drop Down
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    Posted: March 19 2020 at 6:52am

By Scott Weese on March 18, 2020


It’s truly amazing how much we known about COVID-19 and the virus that causes it, SARS-CoV-2, considering we’ve only known about the virus for a few months. However, there are still lots of basic things that we don’t understand.


One important question is whether the environment is a source of infection.

When people breathe, cough, talk or touch surfaces, they can contaminate them. That’s obvious. What that means isn’t as clear. Is the environment an important source of infection, an uncommon source or a non-entity? Some people have stuck to the “There’s no evidence of…” line, something that’s frustrating since ‘absence of evidence’ isn’t ‘evidence of absence.’


So, what is the evidence?


One good thing is the nature of this virus. It’s an enveloped virus. That means it has a fatty external coat, and that’s a good thing for us.

 Enveloped viruses tend to be pretty wimpy outside of their host. They don’t survive well in the environment and they tend to be easy to kill with disinfectants, as opposed to non-enveloped viruses that can live for a long time and be resistant to many disinfectants. So, longterm survival of SARS-CoV-2 isn’t expected. However, can short term survival be a problem? That’s the big question.


A paper in the New England Journal of Medicine (Doremalen et al) looked at the stability of the virus (and its cousin, the original SARS virus) in aerosols and on different surfaces. Some key points were:


The virus remained viable in aerosols for 3 hours (as long as they studied). The infection load decreased but not substantially.  (This isn’t the topic of the post but this result has raised a lot of concern in the medical field).

SARS-CoV-2 survived better on plastic and stainless steel compared to copper and cardboard. While the viral loads decreased, viable virus was still present on plastic after 72hr and on stainless steel for 48hr.

The estimated half live on steel and plastic were 5.6 and 6.8 hours, respectively. That means that it takes that long for 50% of the deposited virus to die. So, after 12 hours, ~25% would be left, and so on.

They concluded “Our results indicate that aerosol and fomite transmission of SARS-CoV-2 is plausible, since the virus can re- main viable and infectious in aerosols for hours and on surfaces up to days (depending on the inoculum shed). These findings echo those with SARS-CoV-1, in which these forms of transmission were associated with nosocomial spread and super-spreading events, and they provide information for pandemic mitigation efforts. “


We don’t know whether the environment is a problem, but we should assume that it is until proven otherwise. That also relates to animals as environmental sources. We should assume that SARS-CoV-2 deposited on a pet’s haircoat by an infected owner can survive for at least a few hours, something that we’re accounting for in our handling guidelines.


Wash your hands, stay home if you’re sick, cough into your sleeve, and practice good cleaning and disinfection. The basics of infection control are pretty…..well…..basic.




'When you feel as though you can't do something, the simple antidote is action: Begin doing it. Start the process, even if it's just a simple step, and don't stop at the beginning.'
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The environment is only a factor if it became contaminated by a human source (infected individual).  

SARS-CoV2 is different than many pathogen, it has no animal reservoir (think of rabies and skunks), no natural reservoir (think of Legionnaire's Disease and water supply) etc.  

Therefore, we can only catch it from contact with another human, either directly (person to person inhalation of virus particles in airborne aerosols) or indirectly (picking up surface contamination from a contaminated doorknob etc., called "fomites"). 

This is why hand hygiene is so essential right now.  All of us have picked up common cold viruses from doorknobs etc. as we have grown, now we have one that might kill us.  However, the virus cannot magically "jump" into our bodies, skin gives a good defense.  This is why hand washing is so important. 

One advantage we have in our fight is that this virus has an envelope that makes it more susceptible to cleaning agents.  This is a good article:  https://www.msn.com/en-us/news/world/how-does-the-new-coronavirus-spread-these-new-studies-offer-clues/ar-BB10cXsz?ocid=msn360

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