[feanaro]

You're right. I also just found out about research (mentioned somewhere downthread) on differences between antibody expression in different tissue types (some IgA subtypes predominantly found in mucosa while other IgG types being dominantly systemic and/or in the lower respiratory system). The discussion there is on a whole other level of precision and points toward a mechanism which might indeed make it possible for vaccinated people to transmit the disease with some degree so it's not quite as clear cut as I presented it.

Though, intuitively, I'd still bet that vaccination will reduce viral shedding and the total load shedded, thus also reducing transmission.