This article was originally published on April 24, 2020. It was updated on August 5, 2020, to reflect new information about this rapidly evolving situation.
While COVID-19 is mainly spread by inhaling tiny droplets released when an infected person talks, coughs or sneezes, large droplets can also land on surfaces. (Hey, another reason to wear a face mask!) A healthy person can then unknowingly touch those surfaces and the next thing you know – the virus has gotten a free ride to wherever and whatever the person touches next.
Often times, people’s hands can transport the viral particles to different surfaces, even the face, where it can enter your body through your eyes, mouth or nose. (Hence why health officials are screaming at us not to touch our faces and to wash our hands.)
Still, viral particles continue making their rounds. (Those mangy freeloaders!) We asked infectious disease specialist Frank Esper, MD, to weigh in on how long the coronavirus can survive on surfaces.
Coronavirus survival by surface
“The virus typically doesn’t like to live on surfaces that have a lot of holes or microscopic little grooves, nooks or crannies,” explains Dr. Esper. “It likes surfaces that are very smooth, like door knobs.”
Early research has demonstrated that the virus’s survival depends on the type of surface it lands on. The live virus can survive anywhere between a couple of hours to a couple of days.
Here’s how long the virus typically lasts on common surfaces, but it can change depending on sanitation efforts, sunlight and temperature:
- Glass – 5 days.
- Wood – 4 days.
- Plastic & stainless-steel – 3 days.
- Cardboard – 24 hours.
- Copper surfaces – 4 hours.
It’s important to note that the amount of live virus decreases over time on surfaces. So the risk of infection from touching something that had the virus on it for a few days (or even a few hours) would lessen the risk.
“As you can imagine cardboard has little microscopic holes in it, so the virus doesn’t like it very much,” says Dr. Esper. “And it doesn’t last too long on fabric either, typically less than a day.”
Figuring out COVID-19’s infectious dose
Viruses can’t survive independently. The whole point of a virus is to invade a living host, hijack it and produce more virus babies. So when an infected person coughs and viral droplets land on surfaces around them, it’s not exactly the outcome that the virus had hoped for.
“If a virus lands on something like a chair or table, it starts dying pretty quick,” explains Dr. Esper. “We may be able to find some viable virus after a few days, but it’s thousands of times less than what was originally deposited by the cough. As soon as the virus hits something that’s not alive and certainly not a human, it’s not going to do very well.”
So just because the virus is detectable on a surface doesn’t necessarily mean that there’s enough there to make someone sick. Scientists are still working to figure out what the infectious dose requirement is to actually cause an infection.
Can coronavirus live on mail?
With online shopping and deliveries now reaching holiday-level busyness, you might be wondering if your mail or packages are carrying the coronavirus. Some people even let their mail or parcels sit for a few days before opening.
“Paper and cardboard are very porous,” says Dr. Esper. “The virus doesn’t like surfaces like that. It likes smooth, even things.”
Coronavirus also doesn’t particularly like to be out in the elements. Certainly, many viruses seem to circulate better in cold weather rather than warm weather, but it bears repeating that if the virus is not in another living person, it’s not going to do well.
“I’m not particularly concerned about catching the virus through the mail,” says Dr. Esper. “We’re certainly studying it and we’ll be able to understand a lot more as time goes on, but the answer is no, I don’t think people need to be concerned about getting the virus through the mail.”