There is a reason that health officials are telling everyone to wash their hands with soap and water as often as you can. It is because, as of the date of this post, there is no vaccine or drug that can help you should you get the coronavirus or COVID-19. It will take millions of dollars to get a working vaccine and officials are saying that vaccine won't be available for 18 months at the earliest. As a result, to the extent possible it is to prevent catching coronavirus, soap and water are your answer. This is because soap dissolves a critical part of the virus, the lipid membrane, destroying it.
The long and short of why soap works has to do with the composition of a virus and the effect soap has on them. All viruses are made up of three components: ribonucleic acid (RNA), proteins and lipids. The weakest component of the virus is the lipid bilayer. As stated before soap can dissolve the lipid bilayer. When this happens the remaining components can no longer function and the virus basically falls apart.
If you remember back to basic biology, you may recall that a virus works by infecting cells. The virus takes over the cell making more of the three components of the virus. Once the cell has been completely used up it bursts. The new viruses can now infect other cells as your body's antibodies work to fight against the virus. The problem is that these new viruses make their way throughout your body and can end up getting coughed out or otherwise excreted by an infected person. Either because the infected person doesn't wash their hands or because they are coughing and not covering their mouth, the virus gets outside the body of the infected individual. Once outside the body, the virus can remain active for hours or even days depending on the surface they land on.
Viruses interact with human skin in a way similar to how things stick to the adhesive side of tape. Individuals come into contact with the virus by touching contaminated surfaces. Once the skin contacts the virus on whatever surface it is on, the virus will "stick". Infection occurs because an individual then unknowingly transfer the virus to the mouth, nose or eyes by touching their face before washing their hands.
Soap is critical in disrupting this process because soapy water inhibits the virus's ability to interact with the skin, destroys the lipid layers of virus and traps the remnants of the virus, washing it away. This prevents the transfer of the virus to the face thus significantly decreasing the risk of infection.
Soap and water will always be the best but in circumstances where that is unavailable, alcohol based sanitizer (with at least 60% ethanol) is a good back up.