Impact of pneumococcal polysaccharide vaccine on incidence and mortality after pneumonia in adults aged ≥60 years—a population-based retrospective cohort study

• Published in: Clinical microbiology and infection Vol. 24; no. 5; pp. 500 - 504
• Main Authors: Kolditz, M., Schmitt, J., Pletz, M.W., Tesch, F.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-05-2018
• Subjects: Age Factors; Aged; Aged, 80 and over; Comorbidity; Female; Humans; Incidence; Male; Middle Aged; Mortality; Outcome Assessment (Health Care); Pneumococcal vaccination; Pneumococcal Vaccines - administration & dosage; Pneumococcal Vaccines - immunology; Pneumonia; Pneumonia, Pneumococcal - epidemiology; Pneumonia, Pneumococcal - mortality; Pneumonia, Pneumococcal - prevention & control; Population Surveillance; Prevention; Vaccination; Vaccination Coverage; Prevention; Pneumonia; Mortality; Pneumococcal vaccination
• ISSN: 1198-743X; 1469-0691
• DOI: 10.1016/j.cmi.2017.08.010

The 23-valent pneumococcal polysaccharide vaccine (PPV) is recommended for prevention of pneumococcal diseases in adults at risk. Few data exist on time-, age- and sex-dependent vaccine effectiveness on outcomes in pneumonia.
We performed a population-based cohort study including adults ≥60 years of age (n = 738 927) based on statutory health insurance data from 2005 to 2011. Primary outcomes were all-cause pneumonia incidence and 30-day all-cause mortality. Pneumonia was identified by International Classification of Diseases, 10th Revision, German Modification (ICD-10-GM) codes, with ambulatory cases validated by antibiotic prescription within 7 days. The effect of PPV within 5 years was analysed after propensity score–based matching (three controls per case with PPV vaccination) including comorbidities, care status, age, sex and influenza vaccination. Evaluations were stratified by age group, sex and time of PPV.
Two-year incidence of all-cause pneumonia in 213 431 vaccinated individuals was 7501 (3.51%) of 213 431 vs. 23 243 (3.63%) of 640 293 in matched controls (difference −0.11, 95% confidence interval (CI) −0.22 to −0.002, p 0.046). After sex-dependent analysis, PPV effectiveness on pneumonia incidence was observed only in women (difference −0.15, 95% CI −0.28 to −0.02, p 0.02). Thirty-day mortality in vaccinated individuals with pneumonia was 1302 (17.36%) of 7501 vs. 4267 (18.96%) of 22 503 in matched controls (difference −1.60%, 95% CI −2.83 to −0.38, p 0.011). After analysis according to age group, significant mortality reduction was present only in adults aged 60 to 79 years (difference −2.31, 95% CI −3.79 to −0.83, p 0.002). Year of PPV vaccination showed no effect on outcomes.
The findings support consideration of sex and age dependence of PPV effectiveness in future studies.