TORONTO — Japanese researchers have found that SARS-CoV-2, the virus that causes COVID-19, can last on skin for up to nine hours, highlighting the need for frequent hand washing to help limit the spread of the virus.
The new study, published earlier this month in science journal Clinical Infectious Diseases, reported that in comparison, the pathogen that causes the flu lasts on skin for about two hours.
“The nine-hour survival of SARS-CoV-2 (the virus strain that causes COVID-19) on human skin may increase the risk of contact transmission in comparison with IAV (influenza A virus), thus accelerating the pandemic,” the study read.
To ensure that test subjects were not infected by the novel coronavirus, researchers at Japan’s Kyoto Prefectural University of Medicine used skin samples from human autopsy specimens. The samples were collected approximately one day after death.
The study reported that skin deteriorates slower after death compared to other human organs, and can still function even 24 hours later.
Researchers reported that the novel coronavirus survived on the human skin samples for 9.04 hours, compared with 1.82 hours for the influenza A virus. When these viruses were mixed with mucus from the upper respiratory tract, to mimic the release of viral particles in a cough or sneeze, researchers found that COVID-19 lasted even longer on the skin at approximately 11 hours.
However, both viruses deactivated on skin within 15 seconds after using alcohol-based disinfectant containing 80 per cent ethanol, which is commonly found in hand sanitizers.
“The longer survival of SARS-CoV-2 on the skin increases contact-transmission risk; however, hand hygiene can reduce this risk,” the study said.
Researchers noted that the study did not consider the “infectious dose” of SARS-CoV-2 or the quantity of virus particles needed to give someone an infection from contact with contaminated skin.
The study also applied the viruses to other surfaces including stainless steel, heat-resistant glass and plastic. The researchers found that COVID-19 stayed active on theses surface for between 58 and 85 hours, whereas the flu lasted around six to 11 hours.
In all the surfaces tested, the study reported that COVID-19 survived far longer than the flu, but researchers acknowledged these results were similar to those of previous studies.
The study’s findings support current public health advice from the World Health Organization (WHO) to regularly and thoroughly wash hands and avoid touching one’s eyes, nose and mouth.
To help limit the spread of COVID-19, the WHO also recommends people cover their mouth and nose when they cough or sneeze and clean commonly used surfaces frequently with an alcohol-based disinfectant.