Vaccinome landscape in nearly 620,000 patients with diabetes.

Introduction: Type 1 (T1D) and type 2 diabetes (T2D) are associated with an elevated incidence of infectious diseases and a higher risk of infections-related hospitalization and death. In this study, we delineated the "vaccinome" landscape obtained with a large immunization schedule offered by the Regional Government of Lombardy in a cohort of 618,396 patients with diabetes (T1D and T2D).

Methods: Between September 2021 and September 2022, immunization coverage for influenza, meningococcus, pneumococcus, and herpes zoster was obtained from the public computerized registry of the healthcare system of Lombardy Region (Italy) in 618,396 patients with diabetes and in 9,534,087 subjects without diabetes. Type of diabetes, age, mortality, and hospitalizations were retrospectively analyzed in vaccinated and unvaccinated patients.

Results: Among patients with diabetes (T1D and T2D), 44.6% received the influenza vaccine, 10.9% the pneumococcal vaccine, 2.5% the anti-meningococcus vaccine and 0.7% the anti-zoster vaccine. Patients with diabetes immunized for influenza, zoster and meningococcus showed a 2-fold overall reduction in mortality risk and a decrease in hospitalizations. A 3-fold lower risk of mortality and a decrease in hospitalizations for both cardiac and pulmonary causes were also observed after influenza, zoster, and meningococcus immunization in older patients with diabetes.

Conclusions: Immunization coverage is still far from the recommended targets in patients with diabetes. Despite this, influenza vaccination protected nearly 3,800 per 100,000 patients with diabetes from risk of death. The overall impressive decrease in mortality and hospitalizations observed in vaccinated patients strengthens the need for scaling up the "vaccinome" landscape in patients with diabetes.