Under the Microscope with Dr. David Weber: Importance of hand hygiene in COVID-19

Author: David Weber, MD, MPH, FSHEA, FIDSA, FMSM (London)

Categories: Clinical Pathogens/Alerts October 28, 2020
Microscope Testing

Under the Microscope with Dr. David Weber explores what’s new in industry literature and provides a synopsis, along with key takeaways.

This Week’s Review:

Survival of SARS-CoV-2 and influenza virus on the human skin: Importance of hand hygiene in COVID-191, authored by Hirose R, Ikegaya H, Naito Y, Watanabe N, Yoshida T, Bandou R, Daidoji T, Itoh Y, Nakaya T. addresses how SARS-CoV-2 has been shown to survive for hours to days on environmental surfaces; however, the survival of SARS-CoV-2 on human skin has not been determined.

The study evaluated the stability of SARS-CoV-2 and influenza A virus (IAV), mixed with culture medium or upper respiratory mucus, on human skin surfaces and the dermal disinfection effectiveness of 80% (w/w) ethanol against SARS-CoV-2 and LAV.  A model was developed that allowed the safe reproduction of clinical studies on the application of pathogens to human skin to elucidate the stability of SARS-CoV-2 and IAV on human skin.  In addition to testing the survival of the viruses on human skin obtained from autopsies, survival was also assessed on stainless steel, glass, and polystyrene.

SARS-CoV-2 was demonstrated to survive for 9.04 hours (95% confidence intervals, 7.96-10.2 hours) while the survival of IAV was 1.82 hours (95% CI, 1.65-2.00 hours).  SARS-CoV and IAV were inactivated more rapidly on skin surfaces than on other surfaces (stainless steel/glass/plastic).  IAV on other surfaces were inactivated faster in mucus versus medium conditions, while SARS-CoV-2 showed similar stability in the mucus and medium; the survival time was significantly longer for SARS-CoV-2 than for IAV [11.09 hours (95% CI, 10-22-12.00 hours) vs. 1.69 hours (1.57-1.81)].  Importantly, both SARS-CoV-2 and IAV in the mucus/medium on human skin were completely inactivated within 15 seconds by ethanol treatment. 

In conclusion, the 9-hour survival of SARS-CoV-2 on human skin may increase the risk of contact transmission in comparison with IAV, thus accelerating the pandemic.  Proper hand hygiene is important to help prevent the spread of SARS-CoV-2 infections.

1Clin Infect Dis. 2020 Oct 3:ciaa1517. doi: 10.1093/cid/ciaa1517. Epub ahead of print. PMID: 33009907


David Weber MD, MPH
Dr. David Weber, Associate Chief Medical Officer for UNC Medical Center Associate Chief Medical Officer for UNC Medical Center


Dr. David Jay Weber received his Bachelors of Arts (B.A.) degree from Wesleyan University in 1973, his Medical Degree (M.D.) from the University of California, San Diego in 1977, a Master’s in Public Health (M.P.H.) from Harvard University in 1985, and completed his medicine residency and infectious disease fellowship at the Massachusetts General Hospital in 1985.

He is Board Certified in Internal Medicine, Infectious Disease, Critical Care Medicine, and Preventive Medicine.  Dr. Weber has been on the faculty of the University of North Carolina at Chapel Hill since 1985 where he is currently the Charles Addison and Elizabeth Ann Sanders Distinguished Professor of Medicine, Pediatrics and Epidemiology in the UNC School of Medicine, and UNC Gillings School of Global Public Health.

He serves as an Associate Chief Medical Officer for UNC Medical Center. He also serves as Medical Director of the Department of Infection Prevention UNC Medical Center. He is the Medical Director of the North Carolina Statewide Infection Control Program (SPICE), a Chair of UNC Biomedical IRB, and serves as the UNC Principle Investigator on the CDC sponsored Duke-UNC Epicenter. Dr. Weber is an Associate Editor of Infection Control Hospital Epidemiology and the Secretary of the SHEA Board. He is the Chair of the NC Health Department’s Tuberculosis Advisory Committee.

Dr. Weber has published more than 470 scientific papers in the peer-reviewed literature and more than 650 total papers and chapters. He is the Senior Editor of Mayhall’s “Hospital Epidemiology and Infection Prevention, 2020”. His research interests include the epidemiology of healthcare-associated infections, disinfection and sterilization, new and emerging infectious diseases (novel influenza, SARS-coV-2, MERS-coV, Ebola, Candida auris), response to biothreats, nontuberculous mycobacteria, control of drug resistant pathogens, immunization practices (especially of healthcare personnel), zoonotic diseases, and epidemiology of tuberculosis.

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