IL-10- and IL-13-Biased T Cell Responses to SARS-CoV-2 Vaccination in Diabetes

Type 1 and type 2 diabetes are associated with increased severity and mortality from respiratory virus infections. Vaccination in the general population significantly reduces the risk of severe respiratory viral infection and triggers a strong, polyfunctional, and lasting T cell response in healthy individuals. However, vaccine effectiveness in people with type 1 diabetes is unclear. Here, we studied the magnitude and functional characteristics of vaccine-specific CD4⁺ and CD8⁺ T cell responses to vaccination in people with type 1 and type 2 diabetes and compared them to those of people living without diabetes, using the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine as a model. We found defects in both CD4⁺ and CD8⁺ T cell memory maintenance and the functionality of the vaccine-specific T cells in people with diabetes compared with people without. In those individuals with type 1 and type 2 diabetes who harbored detectable vaccine-specific T cells, they displayed an unfocused, tolerogenic phenotype characterized by increased expression of IL-10 and IL-13 compared with people without diabetes. These results have implications for vaccination strategies for people with diabetes.