The SARS-CoV-2 coronavirus that causes Covid-19 disease can survive in human skin for at least nine hours much longer than the flu virus according to a new Japanese scientific study. However, research confirms that both viruses are quickly and effectively inactivated by washing and disinfecting hands. Researchers at Kyoto University of Medicine, who published the article in the medical journal Clinical Infectious Diseases used for bioethical reasons skin samples taken from autopsies of people who died a day earlier. Even 24 hours after death, according to Japanese scientists, human skin can be used as an implant, which means it retains most of its functions.
The study found that the coronavirus is much more resistant because it survived on the skin for nine hours, compared to just 1.8 hours for virus A. When the two viruses were mixed with mucus to better mimic conditions where virus particles are found during coughing or sneezing, the SARS-CoV-2 virus survived even longer, around 11 hours, compared to just 1.7 hours for influenza virus.
“The nine hour survival of SARS-CoV-2 in human skin may increase the risk of contact transmission compared to the influenza A virus which accelerates the pandemic,” the researchers said.
However, the coronavirus and influenza virus in the skin were completely inactivated within 15 seconds using a disinfectant solution containing 80% ethanol. “Good hand hygiene leads to the rapid inactivation of SARS-CoV-2 and may reduce the high risk of contact infections,” the researchers said.
A previous US study found that the coronavirus could survive on copper surfaces for as little as four hours (thanks to the antimicrobial properties of copper), on cardboard (for example, packaging) for up to 24 hours, and on surfaces in copper and on plastic or stainless steel surfaces up to 72 hours. Under investigation, according to the new study, remains a crucial question: how many particles of the coronavirus (the infectious dose) is sufficient to transmit the virus to another person after contact with human skin.