Definitely good questions! There's a possibility you still get high viral load, just restricted to immune privileged environments, and that load results in significant asymptomatic transmissibility. Is the load in these environments way way higher in vaccinated individuals - allowing for a new type of asymptomatic spread? Who knows? I will say that I think this idea doesn't really mesh with the current transmission model - I feel like we would be seeing more frequent asymptomatic super-spreaders and transmission from the reinfected. Generally attenuated virus (vs. inactivated) give stronger immune responses because the chemical process of inactivation leads to modification of viral epitopes and lower affinity immunoglobulins against native epitopes upon infection. The mRNA vaccines allow for endogenous expression of the viral proteins and definitely select for very high affinity Igs. The inactivate viruses also have also been implicated in antibody-mediated enhancement for similar reasons - something we should also avoid with the mRNA and adenovirus vaccines!
trashcan wrote:
Well the concern is that vaccinated asymptomatic spread would function differently than unvaccinated asymptomatic spread.
That is absolutely possible. I think it is probable, although very unsure to what degree.
Again I go back to killed vaccines. Is the rather poor ratio of transmission reduction to protection of the vaccinated a result of the generally weaker protection afforded by that kind of vaccine or would the ratio be different from live vaccines regardless of level of protection? I lean towards the latter, and addressing this problem has been the subject of considerable research.
On the plus side I think a lot of the vaccine herd immunity calculations are discounting the effect of previously infected individuals, and the different characteristics of the infected vs the vaccinated with regards to their disease-spreading behavior(as in % needed for herd immunity is different)