Type 1 diabetes is an autoimmune condition where the body’s immune system attacks and destroys insulin-producing beta cells in the pancreas. Without sufficient insulin, glucose cannot enter cells for energy, leading to high blood sugar. The COVID-19 pandemic introduced new challenges for those with Type 1 diabetes. Medical investigation has focused on how the SARS-CoV-2 virus affects individuals with pre-existing diabetes and whether the infection itself can trigger the onset of the disease.
COVID-19 Severity in People with Type 1 Diabetes
Individuals with pre-existing Type 1 diabetes face a higher risk for severe illness from COVID-19, but this risk is closely linked to glycemic management. Well-managed blood sugar can lessen this vulnerability, making outcomes more comparable to the general population. The presence of other health conditions, like heart or kidney disease, can also complicate the body’s ability to fight the infection.
Poorly controlled blood glucose, or hyperglycemia, impairs immune function and amplifies the body’s inflammatory response, which can lead to more severe complications. A severe viral infection also elevates the risk of diabetic ketoacidosis (DKA), a serious condition where the body produces high levels of blood acids called ketones due to a lack of insulin.
Studies found that people with Type 1 diabetes had higher rates of hospitalization and greater illness severity compared to people without diabetes. Research also shows that a history of DKA, higher long-term glucose levels (HbA1c), and hypertension are associated with worse COVID-19 outcomes.
The Link Between COVID-19 Infection and New-Onset Diabetes
Evidence suggests a connection between a COVID-19 infection and the subsequent development of Type 1 diabetes. Research has focused on two primary, non-exclusive hypotheses to explain this link.
One theory proposes a direct viral attack on the pancreas. The SARS-CoV-2 virus enters human cells by binding to ACE2 receptors, which are found on the surface of insulin-producing pancreatic beta cells. The virus may directly infect and damage these cells, impairing their ability to secrete insulin and leading to diabetes.
Another hypothesis centers on the body’s immune reaction. COVID-19 can trigger an intense inflammatory response, or “cytokine storm,” that could inadvertently damage the beta cells. For individuals with a genetic predisposition to autoimmune diseases, this immune activation might initiate or accelerate the autoimmune process where the immune system mistakenly targets its own beta cells.
This is an area of active research, as establishing a causal link is complex. Some cases of new-onset diabetes after COVID-19 may be temporary “stress hyperglycemia” from severe illness, while others are a permanent diagnosis. Researchers are working to distinguish between these possibilities and determine if the virus triggers a new condition or unmasks a pre-existing one.
Blood Sugar Management During a COVID-19 Illness
Managing Type 1 diabetes during a viral illness like COVID-19 requires following established “sick day rules.” Viral infections cause the body to release stress hormones, which raise blood sugar and increase insulin resistance. This response means that even if food intake is reduced, insulin needs may increase.
Frequent blood glucose monitoring, as often as every two to four hours, is necessary. It is also important to check for ketones in the blood or urine, as their presence can signal impending DKA, a medical emergency. Staying well-hydrated by sipping fluids helps prevent dehydration, which can worsen high blood sugar.
Insulin should never be stopped, even with nausea or vomiting. Dose adjustments are often necessary, requiring an increase in both background (long-acting) and mealtime (rapid-acting) insulin to counteract the effects of the illness. Have a plan with your healthcare provider that includes guidelines on when to seek medical help, such as for persistent vomiting or high ketone levels.
Vaccination Considerations for Type 1 Diabetes
Health and diabetes organizations recommend COVID-19 vaccination for individuals with Type 1 diabetes. Clinical trials and subsequent data show the vaccines are safe and effective for this population, with people producing a robust antibody response. While the vaccines are effective, their effectiveness may be slightly lower in people with diabetes compared to those without. This makes vaccination a key safeguard against hospitalization and other serious complications, as the risk of severe outcomes from the virus is higher in this group.
The body’s immune response to the vaccine can cause temporary side effects, including blood sugar fluctuations for a day or two. Monitor glucose levels more frequently in the 24 to 48 hours after vaccination to make any necessary insulin adjustments. This temporary effect is minor compared to the protective benefits of the vaccine.