There isn't as much anecdotal evidence available about the Jansen yet (growing every day). For the the 2-shotters, it definitely seems common for someone who has already been infected to have a reaction on Shot 1, whereas it is more common for someone to have a more significant reaction to shot 2 if they haven't been known to be previously infected.Seems like anyone I’ve heard having a reaction had previously had COVID (of varying degrees). I wonder if the vac is spiking a still increased level of proteins/antibodies.
And the severity of reaction appears to be an individual thing, perhaps linkked in part to the robustness of the subject's immune system. But there are too many variables involved for these simple observations to be more than just simple observations. I will say that I think there are many many incidences of "reactions" where the subject was not known to have been previously infected (for what that is worth).
tl:dr summary: I am not making iron clad pronouncements about anything and will yield the floor to those possessing better information.