CV question for the scientists. Dr P's paper discu

CV question for the scientists. Dr P's paper discusses RANTES and viremia. I have seen discussion regarding aerosol and direct contact transmission. I may have missed it, but I have not seen discussion about how, when and where the virus enters the blood stream. Is a person to be considered ill when the infection is only on their hands, when it enters the nasal cavities, lodges on the eyes or the throat. Are there different therapeutic approaches appropriate in each circumstance? Does the virus first enter the blood stream in the lungs or long before that? Is it easily transmitted by exchange of bodily fluids ? Are we flying blind here or have these issues all been adequately addressed?