TOPLINE:

In Denmark, influenza vaccination coverage among patients with type 1 diabetes (T1D) remained well below the World Health Organization target of 75% throughout 2015-2022, reaching only 16.9% in children and 41.8% in adults by 2022-2023. Lower vaccination rates among adults were associated with insufficient glycaemic control, male sex, and educational attainment of less than 15 years.

METHODOLOGY:

• Researchers conducted a register-based cohort study in Denmark to evaluate influenza vaccine coverage, persistence across multiple seasons, and factors associated with non-vaccination among patients with T1D.
• They included 25,473 patients aged 1-64 years with T1D, contributing 168,212 person-years of follow-up across influenza seasons from 2015-2016 to 2022-2023.
• Patients were stratified into two age groups on the basis of age-specific influenza vaccination recommendations: 1-18 years (paediatric population) and 19-64 years (adult population). The proportion of male individuals ranged from 50.4% to 61.3% across study groups.
• Influenza vaccine coverage was calculated each season as vaccines administered divided by population size. Persistence was defined as the receipt of influenza vaccination in more than 80% of eligible seasons during follow-up.

TAKEAWAY:

• In the paediatric population, influenza vaccine coverage was 5.6% in 2015-2016 and remained stable until a marked increase to 15.7% in 2021-2022 and 16.9% in 2022-2023; in the adult population, coverage was 18.3% in 2015-2016, increased markedly in 2021-2022, and reached 41.8% in 2022-2023.
• In the paediatric population, longer diabetes duration (4-18 years) was linked to lower coverage than shorter duration (1-4 years), with adjusted relative risks (aRRs) ranging from 0.79 to 0.83; furthermore, insufficient vs optimal glycaemic control (A1c levels ≥ 53 mmol/mol; aRR, 0.87) and residence in the North Denmark Region vs the Capital Region (aRR, 0.80) were linked to lower coverage.
• Among adults, male sex (vs female sex: aRR, 0.90) and insufficient glycaemic control (aRR, 0.95) were associated with lower coverage; educational attainment of less than 15 years vs more than 15 years was also associated with lower coverage.
• In the paediatric population, lower vaccination persistence was associated with insufficient glycaemic control and longer diabetes duration; in adults, lower persistence was linked to male sex and a previous episode of diabetic ketoacidosis.

IN PRACTICE:

"Overall, our findings emphasise the need for increased focus on annual influenza vaccination among individuals with T1D, particularly among those with insufficient glycaemic control, adult men, children and adolescents," the authors wrote.

SOURCE:

The study was led by Vithiya Karunakaran and Ida Borreby Pedersen, Steno Diabetes Center Aarhus, Aarhus, Denmark. It was published online on June 14, 2026, in Diabetes, Obesity and Metabolism.

LIMITATIONS:

The study did not capture comorbidities and reasons patients might have chosen vaccination. It also lacked data on healthcare visits and information on coverage or persistence in other vaccination programmes such as COVID. Moreover, as with any observational registry study, residual confounding from unmeasured factors cannot be ruled out.

DISCLOSURES:

Data extraction from Statistics Denmark was funded by a research grant from Flu Lab. One author reported receiving a funded research year salary from Steno Diabetes Center Aarhus. Other authors disclosed having employment; receiving research support, travel support, institutional payments, or consulting fees; participating in advisory boards; and having other ties with various companies.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.