As many countries are fighting a second wave of COVID-19 infections, researchers have found one new explanation for why the disease has higher transmission rates than the flu.
A study published in Oxford University’s Clinical Infectious Diseases journal found that the coronavirus (SARS-CoV-2) lasted approximately 9 hours on skin, while the the influenza virus (IAV) only lasted around 2 hours. They claim this difference may be a key factor accelerating the pandemic and conclude that “proper hand hygiene is important to prevent the spread of SARS-CoV-2 infections.” 
The importance of hand hygiene
While the coronavirus remains stable on human skin for far longer than influenza does, researchers found that the coronavirus did not require a longer period of disinfecting to become inactivated. Both the coronavirus and influenza were, “completely inactivated within 15 [seconds] by ethanol treatment.”  This is an encouraging finding as healthcare workers are preparing to simultaneously fight the ongoing COVID-19 pandemic and an anticipated seasonal wave of influenza.
Thankfully, hand hygiene has remained a focus in public health communication during this pandemic. The World Health Organization has recommended that hygiene stations be placed at the entrances of every public or private commercial buildings. The first item in the American Center for Disease Control’s list of how to protect yourself from COVID-19 is the reminder to wash your hands often.
What is proper hand hygiene?
Because of the increased stability of the coronavirus compared to the flu on skin, researchers believe that “proper hand hygiene is important for the prevention of the spread of SARS-CoV-2.”  But what constitutes proper hand hygiene? The Public Health Agency of Canada recommends washing hands for at least 20 seconds, making sure to clean your palms, back of each hand, between fingers, thumbs and under nails. When using an alcohol-based disinfectant, it is recommended to use 3ml of disinfectant for 30 seconds. (This should be more than enough to keep you safe, as the researchers of this study found that the coronavirus was inactivated after 15 seconds.)
What does this mean for the medical professional—and for the average person?
Healthcare workers already have extensive guidelines for disinfecting surfaces and hands and so far, “no studies to date have definitively demonstrated healthcare-associated transmission via environmental surfaces or healthcare workers’ hands.”  The finding of the longevity of the coronavirus on skin simply underscores the importance of these existing hygienic practices.
Dr. Andreas Glöckner, an infection and intensive care specialist who serves as medical director at OPHARDT Hygiene, spells out what these findings mean for the average person.
“On the basis that we know the coronavirus or other respiratory viruses can live hours or days on inanimate or animate surfaces, there exists the chance to transmit vital viruses [when we touch] these contaminated areas with our hands and then touch our mouth or nose. [If this happens] is it insignificant whether the pathogen can live 2 hours or 2 days, only that the likelihood of infection will be greater. My advice [is to] wash your hands with soap and warm water or disinfect your hands with alcohol based sanitizer before and especially after [coming into contact with potentially infected surfaces or people. We can prevent other infections this way too.”
Despite the differences between the coronavirus and the flu, the same simple practice helps protect us from getting sick from either virus.
 Hirose, R., Ikegaya, H., Naito, Y., Watanabe, N., Yoshida, T., Bandou, R., Daidoji, T., Itoh, Y., & Nakaya, T. (2020). Survival of SARS-CoV-2 and influenza virus on the human skin: Importance of hand hygiene in COVID-19. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, ciaa1517.
 Craig S Conover, MD, MPH, Transmission of SARS-CoV-2 via Contaminated Surfaces: What is to be Done?, Clinical Infectious Diseases, , ciaa1586