A virus has a core of genetic material encased in a protective membrane. The virus reproduces itself by infecting other cells. The membrane is made up of molecules with loose connections.
On contact with water, the membrane’s molecules adhere to each other to repel the water. Surfactants like soap, chemically similar to the membrane’s lipids, lead to the destruction of the virus’ protective envelope.
A lipid is a type of soluble molecule.
Hand sanitizers with at least 60 percent alcohol — or alcohol itself of the same or greater strength — cause the coronavirus’ proteins to deteriorate, as well as weakening the cohesion of the membrane, because the envelope does not work to repel alcohol as actively as it does water.
Pall Thordarson, of Australia’s University of New South Wales, explained that “hand sanitizers and soap are equally efficacious.”
— From Le Monde, March 24