gms | German Medical Science

Background: Since August 2016, the German Committee on Vaccination (“Ständige Impfkommission”, STIKO) recommends pneumococcal vaccination using a sequential vaccination scheme, i.e. pneumococcal conjugate vaccine (PCV13) followed by pneumococcal polysaccharide vaccine (PPSV23) after six months and a booster with PPSV23 every six years in immune-incompetent (“high-risk”) patients aged two years and older as well as in children and adolescents aged 2-15 years with selected underlying chronic diseases (“at-risk”) [1]. The overall aim of this study was to assess the pneumococcal vaccination rates in patients with a first episode of a “high-risk” condition for pneumococcal disease prior to the updated recommendation by STIKO.

Materials and Methods: We conducted a cohort study between January 2011 and December 2016 based on a sample of 4 million subjects from the InGef (former HRI) database. This sample was representative with regard to the age and sex distribution of the German population. The study cohort comprised patients with a first episode of a “high-risk” condition for pneumococcal disease according to STIKO [1] in 2013 or 2014 (pick-up period). In addition, the following inclusion criteria had to be fulfilled: (i) continuous insurance of at least two years before first episode of a “high-risk” condition (e.g., cancer, chronic renal disease, treatment with immunosuppressants) for pneumococcal disease according to STIKO (baseline period), (ii) continuous insurance until the 31 December 2016 (end of the study period) or death and (iii) age of at least two years. Data from 2011 and 2012 was only used to assess baseline characteristics and to exclude patients with prevalent “high-risk” conditions or prior pneumococcal vaccination. Patients were followed from the first episode of a “high-risk” condition for pneumococcal disease (index date) until the end of the study period, death or first documented pneumococcal vaccination. The pneumococcal vaccination rate was calculated as the proportion of patients with a pneumococcal vaccination within two years after the index date. The corresponding 95%-confidence intervals were calculated assuming a binomial distribution. In addition, the median duration from the index date until pneumococcal vaccination was calculated in vaccinated patients and the time to vaccination was assessed on a quarterly basis after the index date. In a further analysis, the distribution of the physician specialty administering the first pneumococcal vaccination was obtained. All outcomes were analyzed overall as well as stratified by region (Eastern vs. Western Germany) and age-group (2-15 years, 16-59 years and 60+ years). In subgroup analyses, we examined patients with a first episode of cancer, HIV, chronic renal disease and patients starting immunosuppressants with and without underlying rheumatoid arthritis. Moreover, the study population was restricted to patients with a first episode of a “high-risk” condition in 2013 to investigate the pneumococcal vaccination rate within 3 years after the index date.

Results: The study cohort comprised 204,088 patients with first episode of a “high-risk” condition with a female proportion of 56.0%. Most patients were in the age group 60+ years with 48.0% followed by 16-59 years and 2-15 years with 47.7% and 4.0%, respectively. The overall pneumococcal vaccination rate within two years was 4.4% (95%-confidence interval: 4.3%-4.5%). After stratification by age group, the highest pneumococcal vaccination rate was observed in patients aged 60 years and older with 7.1% (7.0%-7.3%) followed by those aged 16-59 years with 1.9% (1.8%-2.0%) and the youngest age group with 0.8% (0.7%-1.0%). Within disease-specific subgroups, we found a vaccination rate of 4.7% (4.5%-4.8%) in patients with cancer, 9.9% (7.8%-12.4%) in patients with HIV, 5.7% (5.5%-5.9%) in chronic renal disease patients, 11.5% (9.9%-12.4%) in patients starting immunosuppressants with underlying rheumatoid arthritis and 7.7% (6.9%-8.6%) in patients starting immunosuppressants without underlying rheumatoid arthritis. Stratification by region revealed a slightly higher overall vaccination rate in Eastern Germany (6.5%: 6.0%-6.9%) compared to Western Germany (4.2%: 4.1-4.3%) which was also observed in all age groups and disease-specific subgroups. The median time to vaccination in 8,892 vaccinated patients was 332.5 days (Q1 142 days, Q3 528 days) and patients were vaccinated in a steady manner over the two years after the index date after a small peak in the first quarter. The large majority of patients were vaccinated by a general practitioner with 92.6% followed by pneumologists with 2.3%. The pneumococcal vaccination rate within three years after the index date in patients with a first episode of a “high-risk” condition in 2013 was 6.2% (6.0%-6.3%).

Conclusion: Our study suggests that the overall pneumococcal vaccination rate within two years after a new episode of a “high-risk” condition for pneumococcal disease according to STIKO is very low. Although we may underestimate the vaccination rate due to left truncation and a broad definition of “high-risk” conditions, our findings are in line with other studies from Germany in persons aged 60-64 years [2] and patients with rheumatoid arthritis [3]. To prevent pneumococcal diseases in patients at “high-risk”, further efforts to strengthen the awareness and improve the timeliness of pneumococcal vaccination in practicing physicians are needed, especially in medical specialists taking care of patients with “high-risk” condition according to STIKO.

Conflict of interest: The study and abstract were performed on behalf of Pfizer Germany GmbH.