Utilization of influenza vaccination among chronically ill individuals in Germany: A nationwide claims-based analysis

Individuals with chronic diseases have a higher risk of serious complications or even death in case of influenza infection. The European Union (EU) set a goal to reach a vaccination coverage of 75% in seniors and chronically ill individuals. The aim of this study was to assess influenza vaccination uptake among individuals with a wide spectrum of chronic diseases and examine its regional variations and temporal trends over a period of the last ten years.

We used nationwide SHI-physician outpatient claims data from the years 2009 to 2018 covering 87% of the total German population to assess influenza vaccination uptake among individuals over 1 year of age with at least one of the following chronic diseases: pulmonary, cardiovascular, liver, kidney, metabolic, neurological and musculoskeletal diseases, as well as immune deficiency disorders, including HIV infection.

Influenza vaccination coverage varied across patient populations between 19% (multiple sclerosis) and 44% (chronic kidney disease) in the influenza season 2017/18. Vaccination coverage was slightly higher among females than males, except for HIV/AIDS patients. Among HIV-patients vaccination coverage was higher by 7 percent points among males (43%) than females (37%). The coverage was higher nearly for all patient groups in the eastern than western federal states. Over the observation period vaccination uptake showed decreasing trends in most of the target groups. Among patients with HIV/AIDS and immune deficiency disorders a stagnating trend was observed.

Vaccination uptake among chronically ill individuals is suboptimal and far from the EU-defined target of 75%. There were substantial variations in coverage by disease groups, individual factors and regions. The disease-specific evaluation of the current study allows identification of populations at higher risk with considerable vaccination gaps. Further efforts are needed to improve vaccination uptake in these vulnerable population groups.