Similarly, day 14 S-specific plasma cell responses above the median (79.5 SFU/106 PBMCs) also were associated with a 75% reduction in risk of incident infection [aHR, 0.25 (95% CI, 0.12–0.53); p = 0.01] and day 14 RBD-specific plasma cell responses above the median (25.5 SFU/106 PBMCs) with a 65% reduction in risk of incident infection [aHR, 0.35 (95% CI, 0.15–0.82); p = 0.02] when adjusted for age, sex, and day 14 anti-S1 or anti-RBD titres, respectively. Here, PSMD1 is linked to infection.