So you're saying there's no such thing as asymptomatic spread of COVID-19? Isn't asymptomatic spread a primary reason for the unprecedented restrictions and mass testing?
Edit: Down voters, I would appreciate an explanation for the down votes. Am I missing something simple or is OP mistaken?
You are (mostly) correct. It is pre-symptomatic transmission that has driven most of the spread. By comparison, asymptomatic carriers have been shown in studies to spread the virus much less effectively. People can still get infected after being vaccinated (or having recovered naturally), but they are far more likely to have a truly asymptomatic case and therefore less likely to spread the virus.
That's an interesting distinction I will look into more. Thank you for the reply.
If this is the case, I stand by my questioning of OP's statement: "a vaccinated person, like anyone else, can only transmit the virus if they have a symptomatic breakthrough case."
This one is great because it really brings to light the issue with deciphering the data...
"Since asymptomatic infections represent a large fraction of the infected population, they contribute substantially to community transmission in the aggregate together with presymptomatic cases, even when they individually transmit at a low per capita rate."
You know, I'd almost forgotten about asymptomatic spread, and I'm glad you asked. My assertion about vaccinated was based on a non-scientific interpretation of something I read. I'm afraid I lack the expertise to really answer in depth. So the best I can do is point to the sources that address it. "The viral load in these breakthrough cases was about three to four times lower than the viral load among infected people who were unvaccinated" https://www.scientificamerican.com/article/the-crucial-vacci...
So as best I understand it, the vaccinated are orders of a magnitude less likely to be asymptomatic spreaders, compared to the unvaccinated. As with pretty much everything relating to disease and epidemiology, there are very few absolutes.
Edit: Down voters, I would appreciate an explanation for the down votes. Am I missing something simple or is OP mistaken?