New research out of Japan reveals that the novel coronavirus can survive on human skin for up to nine hours, suggesting that hand washing remains a vital tool in the fight against the pandemic.
The study also shows the coronavirus lasts far longer on human skin and other surfaces compared to the influenza A virus, which causes the seasonal flu. Influenza A survived for just under two hours on skin.
The upside? Both pathogens were killed within 15 seconds upon contact with hand sanitizer, according to the study published Oct. 3 in the journal Clinical Infectious Diseases.
“Taken together, the determined long, 9-hour survival time of SARS-CoV-2 on human skin may increase the risk of viral invasion in the body or its transmission from the skin to other surfaces, with a potential impact in the acceleration of the pandemic,” the researchers from the Kyoto Prefectural University of Medicine in Japan wrote in their study.
“Thus, appropriate hand hygiene using ethanol-based disinfectants leads to the quick viral inactivation and may reduce the high risk of contact infections,” they said.
Past research has shown that the coronavirus can live on copper for up to four hours, cardboard for about one day and plastic and stainless steel for about two to three days, according to an April letter to the editor published in The New England Journal of Medicine.
But studying how long the coronavirus survives on human skin has been excluded from research, mostly because it’s unethical to intentionally slather live virus on someone’s hand.
To get around this, the team from Japan collected three human skin samples from autopsies just one day after death, which the researchers say is OK because skin functions are preserved. They then acquired mucus samples from three individuals to simulate how the virus sticks to surfaces and people via respiratory droplets from coughs and sneezes.
The researchers recorded how long the coronavirus particles remained infectious on skin, in a petri lab dish with mucus, stainless steel, borosilicate glass and polystyrene, a type of plastic.
While the coronavirus survived on human skin for a little over nine hours and influenza A lasted for about two hours, the researchers said the virus’ lifetime was much longer on surfaces. This means “that human skin is less suitable for the survival of viruses.”
Still, the coronavirus lasted eight times longer than influenza on surfaces, the study found.
And thrown into a glob of mucus, the coronavirus survived even longer at just over 11 hours, compared to about an hour and a half for influenza.
But both viruses were deactivated within 15 seconds when 80% ethanol, a type of alcohol, was applied.
The Centers for Disease Control and Prevention says the “primary and most important” way the coronavirus spreads is through close contact with an infected person. The agency also recently acknowledged that the virus can spread via the air when respiratory droplets from coughs and sneezes become smaller and travel greater distances over longer periods of time.
It’s possible people can get infected touching surfaces or objects that have the virus on them before touching their mouth, nose or eyes — “but this isn’t thought to be the main way the virus spreads.”