All - I have been preoccupied by the following questions.
If, to be infected, one needs to ingest 1000 live virus particles, over what duration must that exposure be? In other words, if someone ingests 500 virus particles at noon and another 500 at 2 pm, will that person get infected? What about 500 at noon on Monday and another 500 at noon on Tuesday? Or one week later?
Relatedly, is the reason why it requires 1000 virus particles to infect someone because that level of virus load overwhelms the body's ability to naturally fight it off prior to infection? If it is below that level, is the body more easily fighting off the sub-1000 particle load by building antibodies which may also develop some small amount of immunity to a future infection? If that is the case, if a community passes around low levels of virus over a long period of time, might broad immunity develop such that even with later exposure to heavy virus load, those individuals will not get sick?
Just a couple of thoughts I have had. Interested in the group's response. Thanks all.