As a contrived example... you very carefully sterilize a doorknob and your phone, after walking the dog. But you hang the dog leash with your hand which dragged against the ground which touched someone's viral-feces covered shoes. Now you put your hand in your pocket. You realize you touched a dirty dog leash, so you wash your hands again, but it's futile because now your pocket is contaminated.

It's this never-ending game of wack-a-mole.

Now... I dont believe that's actually how a virus transfers from surface to surface.

The current mental model I hold is more like a video game... that if ANY part of the surface touches any other surface, even for 1 millisecond, both are 100% contaminated at a 100% transfer rate.

In reality, I want to understand more HOW (exactly) viruses transfer between surfaces (say, the ground... sand... a piece of cloth like a sock... etc).

Is it more like if you covered your hands in flour, and you touch 2 surfaces, and get 20% of the flour on the first surface, and then 20% of that 20% where on the second surface (an exponential decrease)?

How does it vary between pourous/non-porous or organic/non-organic surfaces?

Does contact time affect it? How about materials.

I found this study but I don't know how to understand it, I don't read medical journals often. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3531458/

Thanks!