How long does the coronavirus live on surfaces?
Tiny, infected water droplets that drift in the air or land on surfaces have multiplied into a global pandemic.
Typically, an infected person's cough or sneeze spreads SARS-CoV-2 – the coronavirus that causes the disease COVID-19, a highly contagious respiratory illness.
To slow the rising number of infections – tens of thousands of Americans have been infected since Jan. 20 – researchers are looking for the coronavirus' limits. Just how long can it last outside the human body?
According to the New England Journal of Medicine, here's how long the virus could live on a variety of surfaces.
The report also noted the half-life, or rate of decay, of the virus on various materials. That's the time it took for half of the virus sample to die.
The decay rate is important because though the virus may linger on surfaces for days, people are less likely to become infected as the virus dies.
Most infections start with water droplets, tiny globes of water 5 microns or less in size. That's much smaller than a human hair, which is 60 to 120 microns thick.
In all settings, viruses need water to survive. "Viruses can withstand a
small amount of dehydration," says Dr. Paul Meechan, a former director of safety at the Centers for Disease Control and Prevention and president of the American Biological Safety Association.
he problem is knowing "how long it will take a virus to dry out and become noninfectious," Dr. Meechan says. "Eventually, the virus deteriorates and becomes inactive." The speed at which that happens depends on whether the virus is in the air or on a surface.
Let's start with air. Researchers don’t know how many virus-laden particles people infected with COVID-19 expel in the average droplet. An average cough, however, can produce as many as 3,000 droplets and a single sneeze can make up to 40,000, according to multiple studies cited in a 2009 World Health Organization report.
A droplet’s size determines where it goes after being expelled. Gravity forces larger ones to the ground.
"Aerosols are different," says Dr. Stanley Deresinski, clinical professor of medicine and infectious diseases at Stanford University. "Very small particles may be suspended in the air for a long time, sometimes for hours. They're suspended by air currents."
Airborne droplets can stay suspended long enough for someone to walk through and inhale the virus. Outdoors, wind disperses the virus.
A virus that doesn't reach the ground or floor can fall on shared surfaces – or be transferred there by those with the pathogen on their hands. Whatever the case, unsuspecting people can pick it up. How long a virus lives depends on the surface it's on:
How long coronavirus lives on steel
The coronavirus can exist on stainless steel objects for two to three days. That's a problem because steel is commonly used in public transportation and in scores of other public places such as restroom stalls, faucets, and manual paper towel handles.
How long coronavirus lives on plastic
Plastic objects can harbor the virus for two to three days. That's a special concern because many shared items are made of plastic and may not be sanitized often enough or completely enough. Take out food containers, light switches, cellphone cases, elevator buttons and more are commonly made of plastics.
How long coronavirus lives on cardboard
The virus can last on cardboard for up to 24 hours. That's noteworthy because many customers are using online delivery services during the coronavirus outbreak instead of going to stores in person. Food products packaged in cardboard could also be a risk.
How long coronavirus lives on glass
A virus can last as long as four days on glass, depending on location and temperature, according to a separate study by the Journal of Hospital Infection published in January. That report charted the persistence of the SARS-CoV virus, which is similar to the current virus causing COVID-19. Items such as cellphone screens, mirrors and inside glass doors can also support the virus.
How long coronavirus lives on copper
The coronavirus lasted about four hours on copper, a finding consistent with historical use.
"Copper has been used for years," says Dr. Meechan. "Copper ions have been used as disinfectants, they're an effective virucide. It's one of the reasons why old doorknobs were made of brass."
Hospitals are increasing copper use in patient settings, including rails on hospital beds and other shared items.
This is how the reports calculate the survival rate of viruses, in hours, on non-disinfected surfaces:
Cleaning these materials
The CDC defines cleaning as the removal of germs, dirt and impurities from surfaces. Disinfecting involves the use of chemicals to kill pathogens on surfaces. The agency says surfaces should be cleaned using disposable gloves, then disinfected to lower infection risk.
The Environmental Protection Agency has a list of disinfectant products that meet their criteria for use against SARS-CoV-2, the novel coronavirus that causes the disease COVID-19.
SOURCE USA TODAY reporting; New England Journal of Medicine; Stanford University; Centers for Disease Control and Prevention; World Health Organization; National Center for Biotechnology Information; Department of Energy, National Accelerator Laboratory
What you need to know about the pandemic
What does the coronavirus do to your body? Everything to know about the infection process
A visual guide of coronavirus infection, symptoms of COVID-19 and the effects of the virus inside the body, in graphics
s the COVID-19 pandemic spreads across the U.S. – canceling major events, closing schools, upending the stock market and disrupting travel and normal life – Americans are taking precautions against the new coronavirus that causes the disease sickening and killing thousands worldwide.
The World Health Organization and U.S. Centers for Disease Control and Prevention advise the public be watchful for fever, dry cough and shortness of breath, symptoms that follow contraction of the new coronavirus known as SARS-CoV-2.
From infection, it takes approximately five to 12 days for symptoms to appear. Here's a step-by-step look at what happens inside the body when it takes hold.
Coronavirus infection
According to the CDC, the virus can spread person-to-person within 6 feet through respiratory droplets produced when an infected person coughs or sneezes.
It’s also possible for the virus to remain on a surface or object, be transferred by touch and enter the body through the mouth, nose or eyes.
Dr. Martin S. Hirsch, senior physician in the Infectious Diseases Services at Massachusetts General Hospital, said there’s still a lot to learn but experts suspect the virus may act similarly to SARS-CoV from 13 years ago.
“It’s a respiratory virus and thus it enters through the respiratory tract, we think primarily through the nose,” he said. “But it might be able to get in through the eyes and mouth because that’s how other respiratory viruses behave.”
When the virus enters the body, it begins to attack.
Fever, cough and other COVID-19 symptoms
It can take two to 14 days for a person to develop symptoms after initial exposure to the virus, Hirsch said. The average is about five days.
Once inside the body, it begins infecting epithelial cells in the lining of the lung. A protein on the receptors of the virus can attach to a host cell's receptors and penetrate the cell. Inside the host cell, the virus begins to replicate until it kills the cell.
This first takes place in the upper respiratory tract, which includes the nose, mouth, larynx and bronchi.
The patient begins to experience mild version of symptoms: dry cough, shortness of breath, fever and headache and muscle pain and tiredness, comparable to the flu.
Dr. Pragya Dhaubhadel and Dr. Amit Munshi Sharma, infectious disease specialists at Geisinger, say some patients have reported gastrointestinal symptoms such as nausea and diarrhea, however it's relatively uncommon.
Symptoms become more severe once the infection starts making its way to the lower respiratory tract.
Pneumonia and autoimmune disease
The WHO reported last month about 80% of patients have a mild to moderate disease from infection. A case of "mild" COVID-19 includes a fever and cough more severe than the seasonal flu but does not require hospitalization.
Those milder cases are because the body’s immune response is able to contain the virus in the upper respiratory tract, Hirsch says. Younger patients have a more vigorous immune response compared to older patients.
The 13.8% of severe cases and 6.1% critical cases are due to the virus trekking down the windpipe and entering the lower respiratory tract, where it seems to prefer growing.
“The lungs are the major target,” Hirsch said.
As the virus continues to replicate and journeys further down the windpipe and into the lung, it can cause more respiratory problems like bronchitis and pneumonia, according to Dr. Raphael Viscidi, infectious disease specialist at Johns Hopkins Medicine.
Pneumonia is characterized by shortness of breath combined with a cough and affects tiny air sacs in the lungs, called alveoli, Viscidi said. The alveoli are where oxygen and carbon dioxide are exchanged.
When pneumonia occurs, the thin layer of alveolar cells is damaged by the virus. The body reacts by sending immune cells to the lung to fight it off.
"And that results in the linings becoming thicker than normal," he said. "As they thicken more and more, they essentially choke off the little air pocket, which is what you need to get the oxygen to your blood."
“So it’s basically a war between the host response and the virus,” Hirsch said. “Depending who wins this war we have either good outcomes where patients recover or bad outcomes where they don’t.”
Restricting oxygen to the bloodstream deprives other major organs of oxygen including the liver, kidney and brain.
In a small number of severe cases that can develop into acute respiratory distress syndrome (ARDS), which requires a patient be placed on a ventilator to supply oxygen.
However, if too much of the lung is damaged and not enough oxygen is supplied to the rest of the body, respiratory failure could lead to organ failure and death.
Viscidi stresses that outcome is uncommon for the majority of patients infected with coronavirus. Those most at risk to severe developments are older than 70 and have weak immune responses. Others at risk include people with pulmonary abnormalities, chronic disease or compromised immune systems, such as cancer patients who have gone through chemotherapy treatment.
Viscidi urges to public to think of the coronavirus like the flu because it goes through the same process within the body. Many people contract the flu and recover with no complications.
"People should remember that they're as healthy as they feel," he said. "And shouldn't go around feeling as unhealthy as they fear."
Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT.
Javier Zarracina, and Adrianna Rodriguez, USA TODAY
Coronavirus can survive on common materials for hours or even days. Here's what you need to know and how to protect yourself.
How long does the coronavirus live on surfaces?
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