What the studies are observing: people who take all the booster shots are very cautious and careful people…. Obviously they are less likely to get covid.

Upon noting that the quoted study mentions a minimum of 7 days following injection 3, I would guess some portion of the vexed are simply bedridden for a significant amount of that time just due to common reactions to the vexing. If I go with that, there's no granting vexed people any positive traits.