In vitro study shows that gentle cleansers were effective in killing enveloped viruses like COVID-19, but non-enveloped viruses such as the dreaded norovirus displayed resistance against skin-friendly cleansers, as well as harsh soaps.

Gentle cleansers are just as effective in killing viruses – including coronavirus -  as harsh soaps, a new study out University of Sheffield experts has found.

Scientists from the University of Sheffield’s Sheffield Dermatology Research (SDR) group tested antibacterial soap, natural soap, foam cleansers, and bath wash products, with the team investigating their ability to kill both enveloped viruses; such as human coronavirus and influenza, which have an additional layer of structural protection; compared to non-enveloped viruses, such as norovirus and adenovirus.

The findings, published in the journal Frontiers in Virology, show gentle cleansers were effective in killing enveloped viruses, but non-enveloped viruses displayed resistance against skin-friendly cleansers, as well as harsh soaps.  

 “Washing our hands with soap and warm water for 20 seconds was a fundamental message advocated in the UK to help stop the spread of Covid-19. But for healthcare professionals, who can wash their hands as many as 100 times during a 12 hour shift, this may cause unintended adverse effects,” says study author Dr, Munitta Muthana from the University of Sheffield’s Department of Oncology and Metabolism.

“Not only does irritant contact dermatitis cause the skin to become inflamed, blister and crack, which increases transmission of bacteria and viruses, it can also lead to less compliance with personal protective equipment (PPE) and inadequate hand washing for fear of making symptoms worse.”

Contact dermatitis  can also significantly impact workplace productivity.

“For the first time, our study has shown substituting harsh soaps with milder wash products such as gentle cleansers is effective in fighting against enveloped viruses, including human coronavirus, which is very encouraging - especially for those in jobs in which irritant contact dermatitis is an occupational hazard. We also found that using additional agents such as moisturisers to help protect the skin didn’t prevent the products' antiviral activity, which means we don’t have to use very harsh products on our skin in order to kill viruses,”  Muthana says.

The study also found non-enveloped viruses demonstrated greater resistance across all types of hand washing products tested, including harsh chemical substances and milder solutions. Norovirus  was the most resilient.

 “Even when we increased the exposure of norovirus to the handwashing products from 20 seconds to one minute, the virus wasn’t disrupted. Bleach was the only agent which affected the virus - however bleach-based hand washes are not a feasible option due to its corrosivity, which would be extremely harmful to the skin,” adds study author Natalie Winder, PhD Researcher at the University of Sheffield’s Department of Oncology and Metabolism.

“Norovirus can spread very easily - it takes just 18 norovirus particles to infect another person, as opposed to 1,000 coronavirus particles needed to spread the infection. Our findings show that although good hand hygiene practices are important to preventing the spread of many viruses, they are insufficient at controlling the norovirus.”

The study was conducted by the University of Sheffield and funded by CeraVe.