TOKYO (AFP).- The coronavirus remains active on human skin for nine hours, Japanese researchers have found, in a discovery they said showed the need for frequent hand washing to combat the Covid-19 pandemic.

The pathogen that causes the flu survives on human skin for about 1.8 hours by comparison, said the study published this month in the Clinical Infectious Diseases journal.

"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," it said.

The research team tested skin collected from autopsy specimens, about one day after death.

Both the coronavirus and the flu virus are inactivated within 15 seconds by applying ethanol, which is used in hand sanitisers.

"The longer survival of SARS-CoV-2 on the skin increases contact-transmission risk; however, hand hygiene can reduce this risk," the study said.

The study backs World Health Organization guidance for regular and thorough hand washing to limit transmission of the virus, which has infected nearly 40 million people around the world since it first emerged in China late last year.

© Agence France-Presse