How long can the coronavirus live on common surfaces?

  • The virus can live on cardboard for 24 hours—and on plastic and steel for 72
  • There are NO documented cases of infection via common surfaces
  • Make sure to wash your hands after touching common surfaces

Some of the biggest misconceptions about COVID-19 pertain to how long the virus can live on surfaces and how likely a person is to contract the disease by coming into contact with those surfaces. This paranoia was exacerbated, when—earlier in March—the CDC discovered coronavirus genetic material in the cabins of infected passengers on a Diamond Princess cruise ship 17 days after passengers had left the cabins.

Additionally, when the New England Journal of Medicine published a study to determine how long coronavirus can remain on surfaces in a controlled laboratory setting, researchers found that the virus was detectable on copper for up to four hours, on cardboard for up to 24 hours, and on plastic and steel for up to 72 hours.

Though that may sound scary, the good news is that just because the virus is detectable, it still doesn’t mean that you can become infected by coming into contact with it.

Dr. Julia Marcus, an infectious disease epidemiologist and assistant professor at Harvard Medical School, told the Guardian that the important takeaway here is how rapidly the virus decreases on each of those surfaces. As such, “the risk of infection from touching them would probably decrease over time as well.”

In fact, the CDC has yet to document a case in which the virus was transmitted to a person via a contaminated surface.

“It just means that there are parts of the virus that still remain,” added Dr. Akiko Iwasaki, who studies adaptive immunity at Yale School of Medicine. “The virus needs many other components to be intact. Just because you had a little piece of [ribonucleic acid, a nucleic acid present in all living cells], doesn’t mean that there’s an infection.”

So while it is true that the virus can be detected on plastic for up to 72 hours, the amount that remains may be less than 0.1% of the starting virus material—making infection theoretically possible but highly unlikely. Either way, everyone should be diligent about washing their hands, especially when coming into contact with a potentially contaminated surface. 

The best way of sanitizing surfaces and materials

Regardless of how robustly the coronavirus can survive on surfaces, as the old saying goes, an ounce of prevention is worth a pound of cure. To that point, the CDC recommends that cleaning and disinfecting surfaces are still best practices for COVID-19 prevention—as well as the prevention of other viral respiratory illnesses.

Per the CDC, “cleaning” refers to “the removal of germs, dirt, and impurities from surfaces.” Though cleaning does not kill germs, it can remove them and lower the risk of spreading infection. “Disinfecting,” on the other hand, refers to using chemicals like EPA-registered disinfectants to physically kill germs on surfaces.”

When it comes to frequently touched hard surfaces, such as tables, chairs, doorknobs, light switches, handles, desks, toilets, faucets, sinks, and electronics (including phones, tablets, touch screens, remote controls, and keyboards), household cleaners are recommended to regularly clean and disinfect. Make sure to carefully read labels to ensure the safe and effective use of cleaning products. This includes precautions for applying products, such as proper ventilation and rubber gloves.

For soft or porous surfaces, like carpeted floors, rugs, drapes, and linens, you should safely remove visible contamination and then launder these items in accordance with manufacturer instructions using your washing machine’s warmest water setting. Items should then be dried completely.

Sources: Guardian, New England Journal of Medicine, CDC, Johns Hopkins Hub

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