Rubbing hands with ethanol-based sanitizers should provide a formidable defense against infection from flu viruses, which can thrive and spread in saliva and mucus. But findings published in the journal mSphere suggest that that a splash of hand sanitizer, quickly applied, isnt sufficient to stop the influenza A virus.

The influenza A virus remains infectious in wet mucus from infected patients, even after being exposed to an ethanol-based disinfectant (EBD) for two full minutes, report researchers at Kyoto Profectural University of Medicine, in Japan. The secret to the viral survival was the thick consistency of sputum, the researchers found. The substances thick hydrogel structure kept the ethanol from reaching and deactivating the virus.

The researchers first studied the physical properties of mucus and found that ethanol spreads more slowly through the viscous substance than it does through saline. Then they analyzed sputum that had been collected from the patients and dabbed on human fingers. After 2 minutes of exposure to EBD, the IAV virus remained active in the mucus on the fingertips. By 4 minutes, however, the virus had been deactivated. When they repeated their experiments using fully dried mucus, they found that hand rubbing inactivated the virus within 30 seconds.

Physician and molecular gastroenterologist Ryohei Hirose, Ph.D, MD., who led the study with Takaaki Nakaya, PhD, an infectious disease researcher said, “Until the mucus has completely dried, infectious IAV can remain on the hands and fingers, even after appropriate antiseptic hand rubbing… Health care providers should be particularly cautious: If they dont adequately inactivate the virus between patients, they could enable its spread.”

For flu prevention, both the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) recommend hand hygiene practices that include using ethanol-based sanitizers for 15-30 seconds… (Excerpts from the American Society of Microbiology)

Dr KK Aggarwal

Padma Shri Awardee

President Confederation of Medical Associations in Asia and Oceania (CMAAO)

Group Editor-in-Chief IJCP Publications

President Heart Care Foundation of India

Past National President IMA