The Covid-19 virus is actually a weak cell that is made with a fatty outer shell. Globally, hand washing with soap has shown that it slowed down the death rate of communicable diseases in communities in which they don't have access to soap. There are agencies, such as Clean the World, that have made it their mission to re-purpose used hotel soaps and send them to countries that need access to soap. 

Soap by it’s nature has a dual attraction. One end of the molecule is attracted to water but not oil. The other end is attracted to oil and not water. This makes soap an emulsifier. An emulsifier allows something that doesn't normally bond together to combine. Such as oil and water, they just don't mix. This attraction is what make soap so special.

When you wash you hand you wet them and then rub with the soap. The soap creates a lather as you begin to agitate it with the friction of your hands rubbing together. This friction for at least 20 seconds allows the soap to bond to the dirt attached to the oils on your skin containing germs which may include bacteria and viruses.

Our skin has creases and crevices for germs to hide. Washing your hands for 20 seconds allows the soap time to penetrate those areas.

The soaps breaks though the fatty shell of the virus with the fatty loving end of the soap molecule. Once it has broken the shell it can pull the water end inside the cell and neutralizes it.  The cell can't sustain itself, collapses and disintegrates.

Since Covid-19 is a highly communicable disease washing you hands is the best defense against contracting it and sharing it. 

So do as your mother told, "Wash Your Hands."