Washing your hands thoroughly with soap for more than 30 seconds is the most basic hygiene practice to prevent COVID-19 infection. However, in social networks, there are rumors that bar soap, which is commonly used in public toilets, can be a medium for spreading viruses. The reason for the claim is that the soap used by the infected person is contaminated with the virus, so using the same soap can cause coronavirus infection.
However, the virus cannot survive on the surface of bar soap. The envelope that protects the inside of the virus consists of proteins and lipids. Surfactant, a component of soap, can combine with these envelopes to destroy viruses. This is similar to the principle of a hand sanitizer composed of ethanol or isopropanol. Since coronavirus is also an enveloped virus with a lipid envelope, soap can have a strong virus removal effect.
Therefore, even if bar soap is contaminated with coronavirus, the virus is destroyed if you wash your hands thoroughly after foaming for more than 30 seconds. Consequently, there is little concern about COVID-19 infection through solid soap.