Distribution of 13-Valent pneumococcal conjugate vaccine serotype streptococcus pneumoniae in adults 50 Years and Older presenting with community-acquired pneumonia in Israel

Background: Community acquired pneumonia (CAP) is a major cause of morbidity and mortality worldwide, and is a leading cause of hospitalization in previously healthy individuals without predisposing risk factors or comorbidities. In this study we determined PCV13 serotype distribution in adults aged ≥50 years with radiographically confirmed CAP in Israel. Methods: Subjects aged ≥50 years were enrolled from one of three hospitals (Emek Medical Center, Meir Medical Center and Sheba Medical Center) from March 2014 to July 2015. Information was collected on subject demographics, comorbidities, risk factors, and pneumococcal vaccine immunization status. Subjects presented with suspected CAP supported by radiographic evidence, and provided a urine sample and informed consent. Subjects without radiographic confirmation of CAP or who received PPSV23 within 30 days of study enrollment were excluded from the final analysis. Serotype distribution was performed using the urinary antigen detection (UAD) assay and/or microbiological culture. Results: Overall, 498 subjects with radiographically confirmed CAP were enrolled in the study. Eighty subjects (16.1%) were positive for any S. pneumoniae serotype by ≥1 assay, and 38 (7.6%) were positive for PCV13 serotypes via the UAD. The overall 30-day mortality rate was 1.2%, though S. pneumoniae was not isolated from any case leading to death. Conclusion: Despite six years of high pneumococcal immunization coverage in children in Israel, we have shown that 7.6% of CAP cases among adults in Israel remain related to PCV13 serotypes; and that the burden of PCV13 may be as high as 47% of observed pneumococcal CAP.