Hands, crossing point
Measuring 125 nanometers in diameter, the Covid-19 is a hundred times smaller than a human cell. One milliliter of sputum would contain several tens of millions. The virus can stagnate for several hours on a surface and still be harmful. It is usually through the hands that it enters our body. A study published by the American Journal of Infection Control found that an average person touched their face 23 times an hour. Of all face contact, 44% involved contact with a mucous membrane, eyes, nose or mouth, entry points for Covid-19. It is therefore when it is on the hands that it is absolutely necessary to stop it.
A vulnerable membrane
The virus consists of an envelope. It protects its genetic material. It also has around its edge proteins in the form of spikes, these are the "access keys" which allow it to enter host cells to replicate. However, this envelope is made up of lipids, that is to say of fat. And this is its weak point.
The virus destroyed in 20 seconds
The infallible weapon to attack this membrane was invented 2800 years BC by the Babylonians, it is soap. The basic recipe has not changed for more than 4,800 years: mix fat or oil with an alkali such as caustic soda (sodium hydroxide). How it works ? The active ingredients in soap, the surfactants, are pin-shaped molecules, made up of two parts, one that likes water, the other that contains fatty substances. When the soap is in contact with the virus, the part of the surfactants attracted by the fatty substances clings to the lipid membrane of the virus. During rinsing, this part remains attached to the virus, while the part of the surfactants attracted by the water is entrained by the flow and causes the rupture of the membrane. The virus is destroyed and detaches from the skin.
Hydroalcoholic gel
In the absence of water, especially when traveling outside, the alternative to soap is hydroalcoholic gel. It also attacks the envelope of the virus. But to use it, you must have clean and dry hands, the alcohol being deactivated by the presence of too much fat.
