How Long Can Coronavirus Really Live on Surfaces?
Experts Weigh In on New Evidence
When the COVID-19 pandemic first began in March numerous beliefs and claims circulated about how long the novel coronavirus lived on surfaces and how long it was infectious. These claims and beliefs led to questions about how often we should be cleaning and disinfecting surfaces.
While researchers have been able to establish how long a virus could live on the surface, many studies did not answer the question of how long it remained infectious. Telling people the virus can live for weeks at a time causes panic because people assume that translates to the virus being contagious for the same period of time.
Sandra Kesh, M.D., an infectious disease specialist and deputy medical director at Westmed Medical Group believes that the studies done in laboratories do not provide consistent conditions with the environment the virus is living in.
Discrepancies with Studies Done in Laboratories
Another big discrepancy Kesh points out is that when scientists are mimicking human mucus, the substance they use does not contain the white blood cells that human mucus does. This may have the ability to influence the virus’ susceptibility on surfaces differently than in a lab-engineered setting. When we sneeze while sitting on the couch those mucus droplets are not the same as the mucus-like substances seen in labs.
Since the conditions aren’t a perfect match, there is no need to create an additional alarm. It still remains that the primary mode of transmission remains airborne, Dr. Kesh explains.
“The other thing to remember is that the virus is inactivated by UV radiation,” she adds. “Usually, we have sunlight in our homes and have the lights on, too.” The Center for Disease Control and Prevention shared evidence indicating that low humidity and cool temperatures are better suited for the virus to live. Warm temperatures and high humidity do have an impact on the survival of the viruses.
While the conditions in the labs and our everyday environments are different, it is still just as important to maintain consistent cleaning habits. No matter how long the virus lives on the surface, or how long it is infectious, cleaning surfaces is highly recommended.
- Plastic: Research suggests that SARS-CoV-2 can be detected anywhere from 3 to 7 days, and the latest evidence stipulates that infectious virus may persist up until 28 days on non-porous plastic surfaces.
- Metal: On copper, researchers established that viable virus wasn’t detected on this particular metal after 4 hours. Other evidence suggests that stainless steel and metals can play host to the virus between 3 and 7 days.
- Paper: While the Lancet study determined that SARS could be detected on paper money for up to 4 days after first exposure, money was one surface that successfully held onto the virus in the 28-day range in the Virology Journal findings. The Lancet also determined that virus particles couldn’t be detected on printed paper or tissue paper after 3 hours.
- Glass: Initial evidence suggested that virus could be detected on surfaces like windows or our screens on televisions, computers, or smartphones for up to 4 days.
- Cardboard: Food packaging and shipping boxes were initially subject to debate at the onset of the pandemic, as people disinfected their shopping when they returned home. The NEJM study suggests that viable virus couldn’t be detected on cardboard after 24 hours, meaning you might be able to quarantine your shopping outside of the kitchen until then.
- Cloth or non-porous surfaces: While evidence has been limited on this category, the CSIRO team’s research found that common cotton didn’t hold onto the virus beyond two weeks (most of which was inactivated upon first contact).