I'm not aware of stats relating to how many asymptomatic individuals go on to develop full blown symptomatic Covid-19. My assumption is that testing PCR positive while remaining asymptomatic the entire time is by far the most common experience.
Of course, whether you go on to develop symptoms or not, its still highly pertinent information if asymptomatic spread is not a major driver of infection. As long as you self isolate upon symptom onset that should be enough. It does call into question whether isolating the apparently healthy is an evidence-based public health policy intervention though.
Truly asymptomatic spread is not a major driver of infection. There are been some major public relations problems when an organization said this, and were mistaken to mean pre-symptomatic, but the science is pretty clear.
We used to think true asymptomatic infections (never develop any symptoms but test positive) were ~50% of those infected. More recent research puts it at closer to ~20%. Again, some reporting bungled this by reporting studies from controlled populations (like a cruise ship) before they knew if cases were asymptomatic or pre-symptomatic, causing people to quote the number as the former, when it was really a mix.
COVID spreads like wildfire by pre-symptomatic people. There are mountains of evidence to support this. Spread by asymptomatic people is speculation.
> Of course, whether you go on to develop symptoms or not, its still highly pertinent information if asymptomatic spread is not a major driver of infection.
Not sure, but I think you may be using the word "asymptomatic" to denote pre-symptomatic in this sentence.
> As long as you self isolate upon symptom onset that should be enough.
If a person has no symptoms, I think it is reasonable to say they are "asymptomatic".
There is absolutely a difference between 'yet to have' and 'never will have' but I think it is potentially confusing to attempt to delineate between asymptomatic and "pre-symptomatic".
The main concern with messaging that causes confusion in this regard is that a superficial reading of "asymptomatic doesn't spread virus" would imply that if you aren't symptomatic, you aren't a danger.
Every symptomatic person was asymptomatic before they started getting their first symptoms. It might have been few days that they already had the virus on their mucus membranes.
Of course, whether you go on to develop symptoms or not, its still highly pertinent information if asymptomatic spread is not a major driver of infection. As long as you self isolate upon symptom onset that should be enough. It does call into question whether isolating the apparently healthy is an evidence-based public health policy intervention though.