Other theory that I have read, and make some sense, is that it’s not just *an* exposure that can get you sick, but the number and length of the exposures - i.e. once you are swimming in a petri dish of the virus, crammed in with other people who are also sick (whether or not they have symptoms), the more frequent exposures makes you more likely to get sick, and the more exposure you get, the more likely that you will become even sicker - don’t know if that holds up to scientific scrutiny, but makes some sense to me.
Here is an interesting article. “Viral loading” does likely have influence on those who become symptomatic, but this virus is highly contagious and it may not take much if you are susceptible to it. This article also talks about “peak shedding”, which is how much of the virus you are putting out that can infect others.
There is a whole lot we do not know about this virus and that has created a lot of the hysteria because doctors have really struggled with treating patients and obviously our health experts have been all over the map in their assessments.
There are few things in the world more complex than the human body in terms of working parts, systems, and physiology!