New Research Shows COVID-19 Lasts on Surfaces Longer Than Previously Thought

New research shows you may need to keep cleanliness on your mind to keep the SARS-CoV-2 (COVID-19) virus off your hands and surfaces.

Researchers from Australia evaluated the survivability of COVID-19 on various surfaces at three different temperatures. Their study, which was published last week in Virology Journal, shows that at room temperature (68 degrees F), COVID-19 survives on glass, stainless steel, and paper money for longer than previously demonstrated. 

In the early weeks of the pandemic, researchers thought COVID-19 could live for 24 hours on cardboard. (Remember quarantining your packages in the garage?) Although transmission of the virus has since been determined to be strongest in airborne droplets—such as from speaking, singing, sneezing, and coughing—researchers have continued studying how long the virus stays on different types of surfaces in different types of conditions.

The researchers from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia and the Australian Centre for Disease Preparedness (ACDP), are collaborating with researchers in the U.S., U.K., Canada, and New Zealand. Scientists in each country are studying different aspects of the SARS-CoV-2 virus and sharing their results with each other.

“We need to understand how long the virus can remain infectious on different surfaces in order to evaluate the risk of people coming into contact with a potentially contaminated surface,” says lead researcher Shane Riddell, MS, a biorisk pathogen specialist, in an interview published by CSIRO.

Scratching the Surface

When an infected person emits droplets from the mouth or nose—in a sneeze or cough, for example—the virus is encased in mucus, the sticky substance containing white blood cells trying to fight off the invader. To replicate that natural occurrence in the study, the researchers used artificial mucus to carry the SARS-CoV-2 virus. They placed virus-filled droplets onto different materials found in everyday objects, such as cell phones, clothing, vehicles, and appliances, that can carry infection (called “fomites” by scientists).

Researchers found that smooth, nonporous surfaces, such as stainless steel, glass, and vinyl held the virus longer than porous materials, such as cotton. However, paper currency was the exception, as the virus was detectable on it for at least 28 days—the longest of all materials studied. The Australian currency tested in the study involved both paper and polymer bank notes, the latter of which are waxy in feel. In the U.S., “paper” money is actually made of a tight weave of 75% cotton and 25% linen. 

The study was conducted in climate-controlled conditions. Humidity was kept steady at 50% and the tests were done in the dark, because scientists already know that ultraviolet light, such as sunlight, can inactivate the virus. Scientists stored samples at three different temperatures: 68 degrees, 86 degrees, and 104 degrees Fahrenheit (20, 30, and 40 degrees Celsius, respectively). They checked the samples twice the first week, and then once per week for the next month, monitoring the half-life of the virus on each surface.

At 68 degrees, which is considered room temperature in a home, COVID-19 was still detectable on stainless steel, vinyl, glass, and paper currency at day 28. On cotton, the virus stopped being detectable after day 14.

At 86 degrees, which may be normal in a busy commercial kitchen, the virus persisted on stainless steel and glass for seven days. Virus was detectable on paper for up to 21 days.

At 104 degrees, which could represent the interior of a vehicle on a warm day, the virus was not detectable on cotton past the first 24 hours. After 48 hours, all traces of the virus were gone from stainless steel, glass, vinyl and paper money.

How to Disinfect Surfaces

Based on the results of this latest study, here is a cleaning plan for you to try.

Glass

If you have a glass dining table, wipe it before and after every meal with a glass cleaner. Wipe down glass coffee tables or end tables once daily, or at least every other day. If you take public transportation, stick a pack of glass cleaning wipes in your bag or coat pocket for those times you get the window seat. Most importantly, wipe your glass phone screen with an alcohol wipe or electronics wipe several times per day, since it is nearly always in your hand or touching other surfaces.

Stainless Steel

If you have stainless steel appliances, you might not see every fingerprint, but you know the handles get grubby from being touched all day long by everyone in the household. Use stainless steel spray or wipes to clean handles several times per day. Wipe down the main body of appliances weekly. If you are concerned about holding a stainless steel handrail or door handle in public, carry a pack of stainless steel or disinfectant wipes with you.

Vinyl

Car seats are often made with vinyl, as are everyday objects like placemats and tote bags. Placemats should be cleaned with disinfectant spray or wipe before and after meals. Clean a tote bag that you’ve used in public as soon as you get back home, especially the bottom, if you had set it down anywhere. Clean car seats weekly. If you’re on a bus, train, plane or in a cab, or grabbing a shopping cart at the grocery store, pull out a pack of disinfectant wipes and wipe down the seat, tray, or handle.

Cotton

Dish towels, hand towels, bath towels, sheets, and clothes—cotton is everywhere in so many things we touch or wear. Try to use a different dish towel or hand towel daily. Was towels and sheets on the highest temperature setting, or the "sanitize" setting of your washing machine. Use bleach for white towels and sheets, and use a laundry sanitizer product for items that need to be washed in cold water. 

Paper Money

Money "laundering" is not an option, but using a debit card or a service such as Apple Pay is. Consider avoiding handling money right now, if at all possible. Currency in circulation has had a dirty reputation long before this pandemic started.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.