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Covid-19: How long does the coronavirus last on surfaces?
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alexander koryagin
Mar 21, 2020, 5:50:01 AM3/21/20
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Hi, All!
-----Beginning of the citation-----
Covid-19: How long does the coronavirus last on surfaces?
Why can't we stop touching our faces?
We can pick up the Covid-19 by touching surfaces contaminated with the
new coronavirus, but it is only just becoming clear how long the virus
can survive outside the human body.
By Richard Gray
17th March 2020
As Covid-19 has spread, so has our fear of surfaces. There are now some
familiar scenes in public places around the world - people trying to
open doors with their elbows, commuters studiously surfing their way
through train journeys to avoid grabbing a handle, office workers
rubbing down their desks each morning.
In the areas worst hit by the new coronavirus, teams of workers in
protective clothing have been dispatched to spray a fog of disinfectant
in plazas, parks and public streets. Cleaning regimes in offices,
hospitals, shops and restaurants have been increased. In some cities,
well-meaning volunteers even venture out at night to scrub the keypads
of cash machines.
Like many respiratory viruses, including flu, Covid-19 can be spread in
tiny droplets released from the nose and mouth of an infected person as
they cough. A single cough can produce up to 3,000 droplets. These
particles can land on other people, clothing and surfaces around them,
but some of the smaller particles can remain in the air. There is also
some evidence that the virus is also shed for longer in faecal matter,
so anyone not washing their hands thoroughly after visiting the toilet
could contaminate anything they touch.
It is worth noting that, according to the Centers for Disease Control
and Prevention, touching a surface or object with the virus and then
touching one's own face "is not thought to be the main way the virus
spreads". Even so, the CDC, the World Health Organization and others
health authorities, have emphasised that both washing one's hands and
cleaning and disinfecting frequently touched surfaces daily are key in
preventing Covid-19's spread. So although we still don't know exactly
how many cases are being caused directly by contaminated surfaces,
experts advise exercising caution.
One aspect that has been unclear is exactly how long SARS-CoV-2, the
name of the virus that causes the disease Covid-19, can survive outside
the human body. Some studies on other coronaviruses, including Sars and
Mers, found they can survive on metal, glass and plastic for as long as
nine days, unless they are properly disinfected. Some can even hang
around for up to 28 days in low temperatures.
Coronaviruses are well known to be particularly resilient in terms of
where they can survive. And researchers are now beginning to understand
more about how this affects the spread of the new coronavirus.
Neeltje van Doremalen, a virologist at the US National Institutes of
Health (NIH), and her colleagues at the Rocky Mountain Laboratories in
Hamilton, Montana, have done some of the first tests of how long
SARS-CoV-2 can last for on different surfaces. Their study, which has
been published in the New England Journal of Medicine, shows that the
virus could survive in droplets for up to three hours after being
coughed out into the air. Fine droplets between 1-5 micrometres in size
- about 30 times smaller than the width of a human hair - can remain
airborne for several hours in still air.
It means that the virus circulating in unfiltered air conditioning
systems will only persist for a couple of hours at the most, especially
as aerosol droplets tend to settle on surfaces faster in disturbed air.
But the NIH study found that the SARS-CoV-2 virus survives for longer on
cardboard - up to 24 hours - and up to 2-3 days on plastic and
stainless-steel surfaces. (Learn how to clean your mobile phone properly.)
The findings suggest the virus might last this long on door handles,
plastic-coated or laminated worktops and other hard surfaces. The
researchers did find, however, that copper surfaces tended to kill the
virus in about four hours.
But there is a speedier option: research has shown that coronaviruses
can be inactivated within a minute by disinfecting surfaces with 62-71%
alcohol, or 0.5% hydrogen peroxide bleach or household bleach containing
0.1% sodium hypochlorite. Higher temperatures and humidity also tend to
result in other coronaviruses dying quicker, although research has shown
that a related coronavirus that causes Sars could be killed by
temperatures above 56C or 132F (hotter than even a bath scalding enough
to cause injury) at a rate of about 10,000 viral particles every 15 minutes.
Although there is no data on how many virus particles will be in a
single droplet coughed up by an infected person, research on the flu
virus suggests smaller droplets can contain many tens of thousands of
copies of the influenza virus. However, this can vary depending on the
virus itself, where in the respiratory tract it is found and at what
stage in the infection the person is.
The researchers did find, however, that copper surfaces tended to kill
the virus in about four hours
On clothing and other surfaces harder to disinfect, it is not yet clear
how long the virus can survive. The absorbent natural fibres in
cardboard, however, may cause the virus to dry up more quickly than on
plastic and metal, suggests Vincent Munster, head of the virus ecology
section at Rocky Mountain Laboratories and one of those who led the NIH
study.
"We speculate due to the porous material, it desiccates rapidly and
might be stuck to the fibres," he says. Changes in temperature and
humidity may also affect how long it can survive, and so may explain why
it was less stable in suspended droplets in the air, as they are more
exposed. "[We're] currently running follow-up experiments to investigate
the effect of temperature and humidity in more detail."
The ability of the virus to linger for so long only underlines the
importance of hand hygiene and cleaning of surfaces, according to Munster.
"There is a potential for this virus to be transmitted via a variety of
routes," he says.
https://www.bbc.com/future/article/20200317-covid-19-how-long-does-the-coronavirus-last-on-surfaces
----- The end of the citation -----
Bye, All!
Alexander Koryagin
-----Beginning of the citation-----
Covid-19: How long does the coronavirus last on surfaces?
Why can't we stop touching our faces?
We can pick up the Covid-19 by touching surfaces contaminated with the
new coronavirus, but it is only just becoming clear how long the virus
can survive outside the human body.
By Richard Gray
17th March 2020
As Covid-19 has spread, so has our fear of surfaces. There are now some
familiar scenes in public places around the world - people trying to
open doors with their elbows, commuters studiously surfing their way
through train journeys to avoid grabbing a handle, office workers
rubbing down their desks each morning.
In the areas worst hit by the new coronavirus, teams of workers in
protective clothing have been dispatched to spray a fog of disinfectant
in plazas, parks and public streets. Cleaning regimes in offices,
hospitals, shops and restaurants have been increased. In some cities,
well-meaning volunteers even venture out at night to scrub the keypads
of cash machines.
Like many respiratory viruses, including flu, Covid-19 can be spread in
tiny droplets released from the nose and mouth of an infected person as
they cough. A single cough can produce up to 3,000 droplets. These
particles can land on other people, clothing and surfaces around them,
but some of the smaller particles can remain in the air. There is also
some evidence that the virus is also shed for longer in faecal matter,
so anyone not washing their hands thoroughly after visiting the toilet
could contaminate anything they touch.
It is worth noting that, according to the Centers for Disease Control
and Prevention, touching a surface or object with the virus and then
touching one's own face "is not thought to be the main way the virus
spreads". Even so, the CDC, the World Health Organization and others
health authorities, have emphasised that both washing one's hands and
cleaning and disinfecting frequently touched surfaces daily are key in
preventing Covid-19's spread. So although we still don't know exactly
how many cases are being caused directly by contaminated surfaces,
experts advise exercising caution.
One aspect that has been unclear is exactly how long SARS-CoV-2, the
name of the virus that causes the disease Covid-19, can survive outside
the human body. Some studies on other coronaviruses, including Sars and
Mers, found they can survive on metal, glass and plastic for as long as
nine days, unless they are properly disinfected. Some can even hang
around for up to 28 days in low temperatures.
Coronaviruses are well known to be particularly resilient in terms of
where they can survive. And researchers are now beginning to understand
more about how this affects the spread of the new coronavirus.
Neeltje van Doremalen, a virologist at the US National Institutes of
Health (NIH), and her colleagues at the Rocky Mountain Laboratories in
Hamilton, Montana, have done some of the first tests of how long
SARS-CoV-2 can last for on different surfaces. Their study, which has
been published in the New England Journal of Medicine, shows that the
virus could survive in droplets for up to three hours after being
coughed out into the air. Fine droplets between 1-5 micrometres in size
- about 30 times smaller than the width of a human hair - can remain
airborne for several hours in still air.
It means that the virus circulating in unfiltered air conditioning
systems will only persist for a couple of hours at the most, especially
as aerosol droplets tend to settle on surfaces faster in disturbed air.
But the NIH study found that the SARS-CoV-2 virus survives for longer on
cardboard - up to 24 hours - and up to 2-3 days on plastic and
stainless-steel surfaces. (Learn how to clean your mobile phone properly.)
The findings suggest the virus might last this long on door handles,
plastic-coated or laminated worktops and other hard surfaces. The
researchers did find, however, that copper surfaces tended to kill the
virus in about four hours.
But there is a speedier option: research has shown that coronaviruses
can be inactivated within a minute by disinfecting surfaces with 62-71%
alcohol, or 0.5% hydrogen peroxide bleach or household bleach containing
0.1% sodium hypochlorite. Higher temperatures and humidity also tend to
result in other coronaviruses dying quicker, although research has shown
that a related coronavirus that causes Sars could be killed by
temperatures above 56C or 132F (hotter than even a bath scalding enough
to cause injury) at a rate of about 10,000 viral particles every 15 minutes.
Although there is no data on how many virus particles will be in a
single droplet coughed up by an infected person, research on the flu
virus suggests smaller droplets can contain many tens of thousands of
copies of the influenza virus. However, this can vary depending on the
virus itself, where in the respiratory tract it is found and at what
stage in the infection the person is.
The researchers did find, however, that copper surfaces tended to kill
the virus in about four hours
On clothing and other surfaces harder to disinfect, it is not yet clear
how long the virus can survive. The absorbent natural fibres in
cardboard, however, may cause the virus to dry up more quickly than on
plastic and metal, suggests Vincent Munster, head of the virus ecology
section at Rocky Mountain Laboratories and one of those who led the NIH
study.
"We speculate due to the porous material, it desiccates rapidly and
might be stuck to the fibres," he says. Changes in temperature and
humidity may also affect how long it can survive, and so may explain why
it was less stable in suspended droplets in the air, as they are more
exposed. "[We're] currently running follow-up experiments to investigate
the effect of temperature and humidity in more detail."
The ability of the virus to linger for so long only underlines the
importance of hand hygiene and cleaning of surfaces, according to Munster.
"There is a potential for this virus to be transmitted via a variety of
routes," he says.
https://www.bbc.com/future/article/20200317-covid-19-how-long-does-the-coronavirus-last-on-surfaces
----- The end of the citation -----
Bye, All!
Alexander Koryagin
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