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.
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 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).