Risk of celiac disease, type 1 diabetes, and thyroid disease autoimmunity during the SARS-CoV-2 pandemic in South of Sweden: insights from the TRIAD study

Recent studies have implied an increased incidence of autoimmune diseases following the SARS-CoV-2 pandemic. The objective was to determine if SARS-CoV-2 infections were associated with celiac disease (CD), type 1 diabetes (T1D), and autoimmune thyroid disease (AITD) autoantibodies in a population-based screening when the pandemic hit the South of Sweden during 2021 and 2022. Between August 2021 and June 2022 self-obtained capillary plasma samples were collected from 1088 children at 6-9 years of age and 1185 adolescents at 13-16 years of age, who were randomly invited from the general population to a screening for CD, T1D, AITD, and SARS-CoV-2 antibodies. Among children and adolescents screened for autoantibodies associated with CD, T1D and AITD, the SARS-CoV-2 infection rate was increased in tissue transglutaminase autoantibody (tTGA) positive (13/17; 76.5%) compared with tTGA negative (492/1168; 42.1%) 13-16-year-old individuals (<i>p</i> = 0.0057). There was no association between SARS-CoV-2 infection rate and AITD- or T1D autoantibodies. Our findings indicate a potential association between prior SARS-CoV-2 infection and screening-detected CD autoimmunity in adolescents aged 13-16 years. Further research is needed to elucidate whether ongoing CD autoimmunity increases susceptibility to infection or if SARS-CoV-2 may act as a trigger for CD autoimmunity in genetically and environmentally predisposed individuals.