Did COVID-19 Trigger More Type 1 Diabetes Cases? What a Large Swedish Study Found

Between 2007 and 2019, type 1 diabetes diagnoses in Sweden followed a steady upward trend. When the COVID-19 pandemic began, researchers wanted to know: did that trend accelerate? The answer was partially yes. In 2021, type 1 diabetes cases increased by 12% above what would have been expected based on pre-pandemic patterns. In 2022, cases remained elevated by 9%. However, by 2023, diagnoses had returned to the predicted pre-pandemic trend.

This Swedish study, published in Diabetologia in 2025, included all individuals under 30 years old in the country, making it a population-wide investigation rather than a small sample study.

The researchers designed a careful comparison: they matched people who had confirmed SARS-CoV-2 infections with five control individuals of the same age, sex, and region who did not have documented infections. They then tracked whether the infected group developed type 1 diabetes more often than the control group.

The result: across the entire study period, people who had COVID-19 were not at significantly increased risk. The overall risk ratio was 0.96, meaning the infected and uninfected groups developed type 1 diabetes at similar rates.

One finding stood out. Children between 5 and 10 years old who had COVID-19 showed a higher risk of developing type 1 diabetes in the first 28 days after infection compared to uninfected peers. However, when researchers looked at the entire follow-up period—not just the first month—this elevated risk disappeared.

This suggests that if COVID-19 temporarily accelerated diabetes onset in this age group, the effect was short-lived and did not increase long-term risk.

The study raises an important distinction: the temporary rise in type 1 diabetes during 2021–2022 occurred, but it did not correlate strongly with COVID-19 infection itself. Sweden had a non-restrictive pandemic response compared to many other countries, which means factors like school closures, testing patterns, or healthcare delays were different there than elsewhere.

The researchers concluded that the transient increase in type 1 diabetes incidence was likely influenced by broader pandemic circumstances, not primarily by SARS-CoV-2 infection triggering new cases. This finding aligns with earlier inconclusive evidence on whether the virus directly causes type 1 diabetes.

More research is needed to understand why type 1 diabetes diagnoses rose temporarily and whether similar patterns appeared in countries with different pandemic policies.

Source: Diabetologia. Evidence type: PubMed indexed literature. Type1Cure is an information and intelligence hub, not a medical advice service. This article summarizes published research and does not provide diagnosis, treatment, or personal medical guidance. Always talk to your own care team before changing anything about your Type 1 diabetes management.