In addition, while only small frequencies of S‐specific CD8+ T cells from the ND control group secreted other cytokines such as IL‐13, IL‐17A, or IL‐21, these were significantly increased in S‐specific CD8+ T cells from both T1D and T2D participants, suggesting an unfocused memory response to SARS‐CoV‐2 vaccination. Here, IL21 is linked to type 2 diabetes mellitus.