lifespan of coronavirus

Measuring the lifespan of coronavirus on surfaces

The lifespan of coronavirus varies from surface to surface
Monday, September 28, 2020
Drew Bunn

As we continue to make our way through this pandemic, we are learning more and more about it. For instance, we are learning how to treat people who have come down with COVID-19, and we’re also finding out more about the lifespan of coronavirus.

In April 2020, according to a report in Canada’s Globe and Mail, 27.5 per cent of the patients hospitalized with the coronavirus died from it. This percentage had been reduced to 11 per cent by July.

Then, on September 19, the newspaper reported that while there were 401 new cases in Ontario, the highest number registered in a single day since June 7, 2020, the number of deaths from the disease was zero. “The province of 14 million reported no new COVID-19 deaths [making this] the 12th day of zero deaths since the beginning of August.”

That certainly was good news. What may also be good news, especially for those of us in the professional cleaning industry as well as facility management, is that we are learning that the virus may not live on surfaces as long as we first believed.

Lifespan of coronavirus

Back in May 2020, Canada’s CTV News reported that “based on existing research from the New England Journal of Medicine and government agencies,” the lifespan of the virus on various surfaces is as follows:

• Cardboard: one day
• Copper: about four hours, as copper is a natural antimicrobial surface
• Plastic: three days
• Stainless steel: more than three days.

Other studies have found that the coronavirus can live on glass for as much as four days; on wood for two days; and even as long as four days on paper.

However, these numbers are being called into question. This is because a recent study, published in the medical journal, The Lancet, suggests these early studies were conducted in laboratories using large samples of the virus on test surfaces, but “none of these studies present scenarios akin to real-life situations.”

Based on his own testing, using what would be more typical, real-life situations, the author of the report, Emanuel Goldman, PhD, a professor of microbiology, biochemistry, and molecular genetics at the New Jersey Medical School of Rutgers University, stated that, in his opinion, the chance of transmission through inanimate surfaces is very small, and only occurs in instances when an infected person has coughed or sneezed on the surface and someone else touches that surface within one or two hours of the cough or sneeze.

Further, according to Dean Blumberg, MD, chief of pediatric infectious diseases at UC Davis Children’s Hospital (California), “You’d need a unique sequence of events. First, someone would need to get a large enough amount of the virus on a surface to cause infection. Then, the virus would need to survive long enough for you to touch that surface and get some on your hands. Then, without washing your hands, you’d have to touch your eyes, nose, or mouth.”

Other lifespan factors to consider

Measuring how long coronavirus lives on surfaces and how long it can still spread the disease can get complicated. For instance, it deactivates within seconds of landing on a surface. It can live longer on indoor surfaces than outdoor surfaces. Sunlight can impact the lifespan, as can moisture, heat, and cold, all of which make measuring the virus’s lifespan—and gauging its potential to spread COVID—difficult to answer precisely.

What this means for cleaning professionals and building managers

After the 2003 SARS epidemic in Hong Kong, many people said you could smell bleach throughout the city. This was because bleach was used on just about everything and anything, to help stop the spread of the disease.

There was panic, which caused a knee-jerk reaction, resulting in the overuse of bleach. Later, it was found that SARS, as we are learning now with COVID, is most frequently spread from inhalation, not by touching contaminated surfaces.

However, that knee-jerk reaction is being repeated today with COVID. As soon as the pandemic hit our shores, there was a rush by both consumers and cleaning professionals to purchase as many disinfectants as possible. Shortages were common.
Soon, different types of disinfecting systems, including electrostatic sprayers and UV lights, were selected to kill the virus in facilities.

While these systems are not new, they have never been used so extensively on surfaces before the arrival of the pandemic.

However, what we are finding now, several months into the pandemic, is two particularly important things:

1. First, in all too many cases, there has been an overuse of disinfectants, which, while they have proved their value in protecting health, can also be harmful to the user as well as building users when used in such large quantities. In fact, in the U.S., disinfectants are categorized as “pesticides.” Their purpose is to kill living things, which means they must be used with considerable care.
2. Second, disinfectants simply may not be necessary. If these doctors are correct and the virus only lives for a very brief time on surfaces and would require a ” unique sequence of events” to contract the virus from a surface, then all that may be necessary is effective cleaning of surfaces.

Backing this up is a statement from the Centers for Disease Prevention and Control on May 7, 2020: Normal cleaning with soap and water will decrease how much of the virus is on surfaces and objects, which reduces the risk of exposure.

However, we must be careful. If “normal” cleaning refers to mops and cleaning cloths, we may be asking for trouble. We know these cleaning tools quickly become saturated with pathogens as they are used and can spread disease. What ISSA, the worldwide cleaning association, calls “spray and vac,” or “no-touch” cleaning, gently but effectively pressure washes surfaces and fixtures without the use of mops or cleaning cloths, to help eliminate this danger.

Does our discussion mean we should stop using disinfectants? Not necessarily. What we should do is use them more responsibly, realizing that effective cleaning may be all that is required.

Drew Bunn is Canadian Director of Sales for Kaivac Canada, manufacturers of professional cleaning tools and equipment engineered to help protect health and stop the spread of infection. He can be reached at dbunn@kaivac.com.

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