Some things have drastically changed since the COVID-19 pandemic first started. Do any of these strange (but now familiar) scenes sound familiar: People touching elbows instead of shaking hands, office workers wiping their desks down every morning, and subway commuters balancing carefully without touching any handlebars.
Many people have gone to great lengths to prevent any transmission of COVID-19. But are any of the efforts we just mentioned actually effective coronavirus protection measures to take? With that said, how long does COVID-19 actually stay active on surfaces? Let's find out.
Some Concerns Are Only Surface-Level
COVID-19 usually spreads through tiny droplets released from an infected person's coughing, sneezing, and even talking. This is similar to how other respiratory illnesses like the flu transmit. 3000 droplets can be released from just one cough. Larger particles tend to land on other people and the surfaces around them. And the smaller ones? They can stay airborne for quite some time.
A study published by the Imperial College London showed viral DNA left on an isolated hospital bed rail had managed to spread to 18 other surfaces. The scariest part? It had done so in only ten hours. These surfaces ranged from children's toys in the play area to door handles and waiting room chairs. While this research focused on a virus that infects plants instead of COVID-19, it elucidated just how far a virus can spread.
How Long Does the Coronavirus Last on Surfaces?
If you felt a need to panic after reading about the study we just mentioned, you're certainly not alone. But here's the good news: Touching a coronavirus-contaminated surface and then touching your own face is "not thought to be the main way the virus spreads," according to the Centers for Disease Control and Prevention (CDC).
The CDC later updated this guidance to state that COVID-19 does spread "very easily" through contaminated aerosol droplets. Still, the CDC, the World Health Organization, and other health officials have emphasized that sanitizing your hands and frequently touched surfaces are essential to preventing COVID-19's spread.
In the case of school, restaurant, and public place reopenings, the CDC does still believe that intensified sanitizing of surfaces is still needed. Essentially, while it's not exactly clear how many COVID-19 cases are due to transmission through contaminated surfaces, experts still advise that we exercise caution.
Coronaviruses are known to be resilient in terms of where they can survive. A National Institutes of Health (NIH) study found that the coronavirus can survive on plastic and metal for up to two or three days without proper disinfection. A more recent study by microbiologists in Beijing found that it can survive and remain infectious on steel, glass, latex, and ceramics for up to seven days. In low temperatures, another study found that it can even linger for as long as 28 days.
Here's How to Clean Coronavirus-Contaminated Surfaces
The NIH researchers did find that copper surfaces tend to kill the virus in approximately four hours. If you want to learn more about why copper works so well against the coronavirus, check out this article. While impressive, four hours is still quite long. Luckily, there's a faster option.
Research shows that disinfecting surfaces with 62 to 71% alcohol, 0.5% hydrogen peroxide bleach, or household bleach with 0.1% sodium hypochlorite can inactivate coronaviruses within 60 seconds. Humidity and high temperatures also seem to help in causing the virus to die quicker. The US Environmental Protection Agency (EPA) has published a list of disinfectants that work well against the coronavirus, which you can see here.
Beyond these measures, ultraviolet light is also considered a valid way to disinfect surfaces. But it's not recommended for use on human skin.
Air Is the Primary Transmission Medium
Perhaps more importantly than their findings on surfaces, the NIH study did also discover that coronavirus droplets can survive for as long as three hours after being coughed out into the air. And the smaller the droplet, the longer they can linger — aerosols between one to five micrometers in size can stay active for several hours.
Surface studies have caused many people to become paranoid and even exaggerate the risk of COVID-19 transmission through this medium. Emmanuel Goldman, a professor of microbiology, molecular genetics, and biochemistry at the New Jersey Medical School of Rutgers University, had this to say in a response published in The Lancet Infectious Diseases:
"In my opinion, the chance of transmission through inanimate surfaces is very small, and only in instances where an infected person coughs or sneezes on the surface, and someone else touches that surface soon after the cough or sneeze (within 1-2 hours)."
Essentially, it would take the perfect combination of events to occur for a person to become infected with COVID-19 via surfaces. It's also worth noting that the majority of surface studies have focused on how long the coronavirus stays active on surfaces, not if you can catch it from them.
With all this said, it's still better to be safe than sorry. Practice caution when you are out in public. Make sure to wear a face mask or 2-ply neck gaiter. And continue to sanitize your hands and commonly touched surfaces regularly.