How long does coronavirus live on surfaces? How to disinfect and kill viruses

Which surfaces are the most infectious and how do you disinfect them? Experts weigh in.
/ Source: TODAY

Touching any surface suddenly seems dangerous in the era of the new coronavirus.

Fingers might pick up the microbe, which could lead to COVID-19 — the illness spreading around the world — when a person touches his or her face.

How long does coronavirus live outside the body?

The Centers for Disease Control and Prevention estimates it could be viable for “hours to days.”

A preliminary study published this week found the virus could be detected in the air for up to three hours after it was aerosolized with a nebulizer, up to four hours on copper, up to 24 hours on cardboard and up to two to three days on plastic and stainless steel.

The newest research, which has not yet been peer reviewed, was conducted by scientists at the National Institutes of Health, Princeton University, the University of California and the CDC.

Previously published studies have indicated coronaviruses in general — not specifically the new one — can last up to nine days on surfaces depending on the surface type, the heat, the humidity, exposure to sunlight and other factors, said Joseph Fair, a virologist, epidemiologist and NBC News Science contributor.

“Coronaviruses have been with us for millions of years — not this one, but other coronaviruses,” Fair told TODAY.

Since there’s no definitive data on the new bug yet, scientists have to err on the side of caution about how long it can stay active, he added.

It’s important to note there hasn’t been a documented case of a person getting infected from a surface contaminated with the new coronavirus, according to the CDC.

Transmission usually happens when people come in direct contact with respiratory droplets produced when a nearby infected person coughs or sneezes.

How does that compare to other germs?

The flu virus can stay active on some surfaces for up to 48 hours, according to the CDC.

The Ebola virus can survive on doorknobs and countertops for several hours.

The norovirus can survive up to four weeks on surfaces, said Charles Gerba, a professor of microbiology and immunology at The University of Arizona.

Some bacteria can last much longer, Fair said.

What affects how long the coronavirus stays active?

Fair called sunlight “nature’s greatest disinfectant” because the ultraviolet light inactivates bacteria and viruses.

Higher heat and humidity, on the other hand, will help it to stay active longer, he noted.

Disinfecting surfaces can kill the virus. More on that below.

Does the type of surface make a difference?

Yes, the less porous a surface, the more virus you will get on your hands when you touch it, Gerba said.

“You will pick up on your finger 70% of the viruses on stainless steel surfaces versus only 1% from a cloth surface or money,” he noted.

That being said, Fair advised people to avoid handling cash, which he called “one of the most filthy things in our society, period.” Paper money is made of cotton, an absorbable surface that can get wet. The new coronavirus can potentially stay active on it for up to nine days just like on other surfaces, he said.

Which surfaces are the most infectious?

Any that are touched the most often, Fair said. That includes bathroom faucet handles, doorknobs, elevator buttons, hand rails and touchscreens on phones, tablets, and ATMs.

They’re the dirtiest surfaces we come into contact with because so many people touch them.

What kills viruses?

Common cleaners with either bleach or alcohol as their active ingredient inactivate infectious viruses, Fair said.

Coronaviruses are fairly sensitive to most disinfectants, including bleach, hydrogen peroxide and quaternary ammonium compounds, Gerba added. If the label says the cleaner will kill the influenza virus or norovirus, it will work against coronaviruses, too.

“I would use disinfecting wipes because then you use the right dose of disinfectant and you usually let it dry so you get the right contact time for the disinfectant to work,” he noted.

How often should you disinfect surfaces?

Several times per day, especially frequently-touched items like a computer keyboard, phones and tablets, Fair advised.

“It’s very good practice because those are the filthiest areas in your life,” he said.