How Long Can Germs (Like the Coronavirus) Live on Surfaces at Home?
If you’re in close enough proximity to someone who’s sick, you can become infected by the droplets expelled from their nose or mouth when they sneeze or cough. But droplets can linger on surfaces, too. So there is a possibility you can catch the illness if you touch your face after touching an infected surface. Fortunately for everyone, germs can’t survive indefinitely outside the body—and how long they remain “viable” can vary drastically.
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Dr. Elizabeth Scott, professor of microbiology at Simmons Center for Hygiene and Health in Home and Community at Simmons University in Boston, says how long germs live on surfaces depends on the specific pathogen, whether it’s a bacteria or a virus, and the nature of the surface it’s on.
For example, she says most bacteria and fungi can survive for months on dry surfaces. For viruses, how long they survive depends on the nature of the viral cell. Viruses with an outer layer called an “envelope” are generally more vulnerable to being inactivated, while viruses without an envelope survive longer. Non-enveloped viruses, such as adenovirus and rhinovirus (which cause cold-like symptoms) and hepatitis A can live for up to three months on contaminated surfaces. Enveloped viruses, including herpes, influenza, and coronavirus, generally remain infectious for hours or days, rather than months.
How long does coronavirus live on surfaces?
Researchers are only beginning to understand how long the novel coronavirus can survive on surfaces. A recent study, that has now been peer-reviewed, shows SARS-CoV-2, the virus that causes COVID-19, can remain viable on hard surfaces like plastic and stainless steel for up to 72 hours, and on cardboard for up to 24 hours. But the novel coronavirus is less likely to live that long on other surfaces—in the study, the virus remained viable on copper for about four hours. The lab results might not be a direct indication of what’s happening inside your home or out in the world—the tests were conducted in a rotating drum, not on a door handle.
According to the International Forum on Home Hygiene, the novel coronavirus’ infectivity declines over time, and it’s most likely to infect someone immediately after it’s expelled from the infected person. The most likely surfaces to spread droplets of infected mucus are high-touch surfaces like handkerchiefs and tissues, faucets and door handles, toilet seats and flush handles, phones, mobile devices, and TV remotes.
The CDC says it hasn’t documented any cases of people becoming infected with the novel coronavirus from infected surfaces (also called “fomites”), and that inflection is much more likely to occur through direct contact with respiratory droplets (aka being near someone who’s coughing).
How often should you disinfect surfaces in your home?
If someone sick was in your home, it’s important to disinfect high-contact surfaces so you don’t transmit their germs to yourself and others. That’s the premise of a disinfecting philosophy called targeted hygiene.
With targeted hygiene, Scott says, there’s no hard-and-fast rule about how often to disinfect surfaces in the home, or when it’s OK to stop disinfecting after someone feels better. Instead, use common sense to focus on disinfecting high-contact or high-touch areas, especially when someone is feeling sick or recovering from an illness. “Targeted disinfection should be happening continuously in order to reduce the risks of infections at home,” says Scott.
In the case of the novel coronavirus, it’s still not clear if and for how long people continue to shed the virus after they no longer show symptoms—and because of how rapidly it seems to spread, it’s quite likely that someone else in the household will become infected if one person has it. In other words, it’s better to be over-cautious and hyper-vigilant when it comes to disinfecting surfaces in your home.
“My advice would be, always follow targeted disinfection guidelines for common touch surfaces and food contact surfaces,” Scott says. “And in the current situation, keep it up until the epidemic has come to an end.”
Read all of Apartment Therapy’s disinfecting coverage.