Publication date: Jun 15, 2026
A possible association between infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and type 1 diabetes (T1D) development has been reported. Whether SARS-CoV-2 infection affects beta-cell loss in T1D over time is unknown. We investigated this in adults with new-onset T1D. Individuals with new T1D were included from six Danish hospitals between December 2020 and January 2023. Within one month after the diagnosis of T1D, we assessed medical history, previous self-reported COVID-19 infection, COVID-19 vaccination, glycated haemoglobin (HbA1c), and SARS-CoV-2 antibodies (Cov2IgG). A mixed-meal tolerance test (MMTT) was performed after overnight fast at baseline, and after 12 and 24 months to assess plasma glucose and C-peptide at 15-60 min intervals for up to 150 min. The main outcome was C-peptide area under curve (AUC), as a measure of residual beta-cell function, in Cov2IgG negative and positive individuals. A total of 94 individuals with T1D were included (34% were female) and 90 had available MMTT results. The mean age was 30. 9 (SD 10. 2) years, the mean HbA1c was 108 +/- 25 mmol/mol (12. 1 +/- 2. 29%), at enrolment. 17% were Cov2IgG positive at enrolment, indicating preceding COVID-19. The baseline median AUC was 652 (25-75%: 458-937) pmol/l for Cov2IgG negative vs. 703 (564-1099) pmol/L for Cov2IgG positive individuals (P = 0. 29). After 12 months, (N = 81), the AUC was 662 (394-892) vs. 594 (532-973) pmol/L in the two groups, respectively (P = 0. 57). After 24 months, (N = 47), the AUC was 452 (244-792) vs. 535 (380-882) pmol/L (P = 0. 55). Seroconversion to CoV2IgG positivity did not affect AUC at 12 months (P = 0. 53). Cov2IgG status did not alter HbA1c at baseline or follow-up (P = 0. 86). Among persons with new-onset T1D, 17% were Cov2IgG positive during the pandemic, which was higher than in the Danish background population. Assessed by MMTT, COVID-19 infection prior to T1D development did not affect insulin secretion or glycaemic control. NCT04623697 (registered on the 10th of November, 2020).
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| Concepts | Keywords |
|---|---|
| Coronavirus | Clinical diabetes |
| Danish | Clinical science |
| Diabetes | Epidemiology |
| Nct04623697 | Islet damage |
Semantics
| Type | Source | Name |
|---|---|---|
| disease | MESH | COVID-19 |
| disease | MESH | infection |
| disease | MESH | type 1 diabetes |
| disease | MESH | severe acute respiratory syndrome |
| pathway | REACTOME | SARS-CoV-2 Infection |
| disease | MESH | included |
| drug | DRUGBANK | Dextrose unspecified form |
| pathway | KEGG | Insulin secretion |
| disease | MESH | Long Covid |
| pathway | REACTOME | Reproduction |
| drug | DRUGBANK | Angiotensin II |
| disease | MESH | ketoacidosis |
| drug | DRUGBANK | Glutamic Acid |
| drug | DRUGBANK | Gold |
| drug | DRUGBANK | Fenofibrate |
| disease | MESH | fatigue |
| disease | MESH | fever |
| disease | MESH | cough |
| disease | MESH | sore throat |