Health officials have not yet documented the transmission of the new coronavirus from contaminated surfaces, but because they think it spreads through droplets, they’re encouraging people to clean and disinfect frequently touched surfaces and objects, such as doorknobs and faucets.
Practising good hand hygiene, covering your mouth and nose when you sneeze, and cleaning and disinfecting oft-handled items “are the most important ways that you can protect yourself and your family from respiratory illness, including COVID-19,” according to the Public Health Agency of Canada’s website.
But which surfaces should you pay attention to most? And how should you clean and disinfect for the virus? Here’s a guide:
How long can the coronavirus survive outside the body?
In a controlled laboratory environment, coronaviruses can live for a few hours or up to a day on a surface. But when they are shed out of people’s noses or mouths, the organic load – in other words, “snot” – can help preserve them a little longer, about a couple of days to a maximum of five, says Jason Tetro, author of The Germ Code and The Germ Files.
The virus that causes COVID-19 is spread through airborne droplets by coughing or sneezing, through touching a surface those droplets have touched, or through personal contact with infected people.
Wash your hands frequently and thoroughly
The World Health Organization recommends regular hand-washing and physical distancing – that is, keeping at least two metres from someone with a cough. If you have to cough or sneeze, do it into your sleeve or a tissue, not your hands. Avoid touching your eyes, mouth or nose if you can.
The CDC says to frequently clean dirty surfaces with soap and water before disinfecting them.
- If you show symptoms of COVID-19, seek medical attention and do what your health-care provider recommends. That may include staying home from work or school and getting lots of rest until the symptoms go away.
COVID-19 is much more serious for older adults. As a precaution, older adults should continue frequent and thorough hand-washing, and avoid exposure to people with respiratory symptoms.
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So far, the evidence suggests the new coronavirus that causes COVID-19 can survive for hours to days on a variety of surfaces, according to the U.S. Centers for Disease Control and Prevention (CDC). It says, however, that transmission of coronaviruses is more common through respiratory droplets than contaminated objects or materials, and that the latter route of transmission has not been documented for the new virus.
Mr. Tetro explains this has to do with its minimal infectious dose. That is, you need to introduce a certain amount of the virus into the body for it to gain hold and start an infection.
“Perhaps there’s not enough of the virus that’s coming out of somebody, and coming onto a surface for somebody [else] to touch it, pick it up and reinoculate themselves,” he says, though he cautions it’s still not known what the minimal infectious dose of the new virus is.
How do you get rid of the virus?
Coronaviruses, much like flu viruses, are called “enveloped,” which means they have a shell made of lipids or fats, Mr. Tetro says. Thus, any surfactant, such as regular soap or a household product that breaks up fat, will be effective against the new virus.
For households, the CDC says people should wear disposable gloves, which should be thrown out after each use, to routinely clean and disinfect frequently touched surfaces, such as tables and light switches. They should also wash their hands immediately after removing the gloves.
Dirty surfaces should be cleaned with soap and water before disinfecting them, the CDC advises. For disinfection, it says diluted household bleach, solutions with at least 70 per cent alcohol, and household disinfectants registered with the U.S. Environmental Protection Agency should be effective. (For bleach, use five tablespoons for every four litres of water.)
Disposable gloves should also be used when handling laundry of anyone ill, the CDC says. To minimize the possibility of spreading the virus by air, avoid shaking out dirty laundry, it says. Launder items according to manufacturers’ instructions, using the warmest water settings possible and dry completely. And clean and disinfect clothes hampers, it says.
How can you navigate germy surfaces in public?
Many buildings now are designed to reduce the need for people to touch surfaces, with elements like automatic doors, door-less entries to washrooms, and automatic taps and towel dispensers, says Stephen Hoption Cann, an epidemiologist and clinical professor at the University of British Columbia’s school of population and public health.
If you can’t avoid contact, though, try not to use your hands. Instead, you can use a sleeve of your coat or a paper towel to open doors or push elevator buttons, he suggests.
Your likelihood of getting sick from touching a public surface or object can vary, Mr. Tetro says. Items like cafeteria trays or tables can be more risky, since they are touched by numerous people and are handled more than just fleetingly, he says. By comparison, the hand rails of the stairs to a subway station may be touched by just as many people, but not likely long enough to spread a lot of germs.
Regardless, it’s best to frequently wash your hands or use hand sanitizer, as instructed by health officials. Until more is known about the new coronavirus, it’s impossible to say you won’t get it from touching surfaces, Mr. Tetro says.
Health Canada recommends washing hands with soap and water for at least 20 seconds, using regular soap and warm water, and wiping them dry.
When using hand sanitizer, Mr. Tetro says you should cover your hands so that they are wet for a minimum of 15 seconds.
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Editor’s note: (March 10, 2020): A previous version of this story incorrectly identified Jason Tetro as a visiting scientist at the University of Guelph.
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