Background
Pneumococcal infections contribute largely to communicable disease morbidity and mortality in vulnerable populations. In addition to other vulnerable groups, the German Committee on Vaccination (Ständige Impfkommission, STIKO) therefore recommends pneumococcal vaccination in adults ≥60 years and some chronically ill patients, including those with immunosuppression but also chronic diseases of the heart or respiratory conditions at higher risk of infection. For the latter, STIKO recommends repeated vaccinations at least every 6 years.

The Robert Koch Institute (RKI) monitors and reports pneumococcal vaccination coverage rates (VCRs) annually in its epidemiological bulletin; however, information on pneumococcal VCRs by indication is not published.

Materials and methods
We conducted a retrospective cohort analysis using a representative health claims research database (InGef database) with 4.3 million insured residents in Germany. Patients suffering from chronic diseases who were ≥16 years in 2019 were included. International Classification of Diseases, 10th revision, German Modification (ICD-10 GM) codes were used to identify the underlying disease.

To determine pneumococcal VCRs for these patients, we used standard documentation codes for pneumococcal vaccinations and evaluated the years 2014 to 2019. Additionally, of all patients ≥16 years with chronic diseases in 2019, we examined the re-vaccination rate 6-7 years later (2018 and 2019) in those who had received a previous vaccination in 2012 or 2013. All results were stratified by age groups and specific disease entity.

Results
The overall pneumococcal VCR in patients aged ≥16 years with chronic cardiac diseases was 24.11%. The VCR increased with increasing age and was lowest in patients aged 16-29 years (2.77%) and highest in patients aged 70-74 (31.78%).

The pneumococcal VCR was highest in patients with heart valve disease (27.58%), followed by coronary heart disease (26.70%), heart failure (26.67%) and atrial fibrillation (25.03%).

The overall re-vaccination rate of vaccinated patients aged ≥16 years with chronic cardiac diseases was 25.58%, and highest in patients with heart failure (27.42%), followed by those with heart valve disease (26.55%), atrial fibrillation (24.74%) and coronary heart disease (24.70%). The highest re-vaccination rate was seen in patients aged 65-69 years (31.08%), the lowest in those aged 40-49 (13.40%).

Conclusions
STIKO’s recommendations on pneumococcal vaccination in patients suffering from cardiac diseases are not sufficiently adhered to; only one in four patients with chronic diseases of the heart has been vaccinated. Awareness of pneumococcal disease burden and the importance of protective vaccine programs must be increased in both patients and their physicians.