Pediatric Community- Acquired Bacteremia Before and After the Introduction of the Pneumococcal Conjugate Vaccine into the National Immunization Program in Israel

Abstract

Background. The 7-valent pneumococcal conjugate vaccine (PCV7) has been part of the national vaccination program (NVP) in Israel since July 2009, and was replaced by 13-valent pneumococcal conjugate vaccine (PCV13) by November 2010. The current study was performed to determine the impact of routine pneumococcal vaccination on patterns in community-acquired bacteremia (CAB) in the Pediatric population in Israel. Methods. Retrospective chart review of children aged 0-18 years that arrived to three tertiary care pediatric hospitals between January 2007 and December 2015 with CAB. Patients' charts were retrieved for demographic, clinical and microbiological data, final diagnoses and outcome. Results. 554 children were included. Significant reduction was found in admission rate due to pneumococcal bacteremia (from 250.4/100,000 to 115.2/100,000; 54% reduction), lower respiratory infections (from 142.1/100,000 to 80.9/100,000; 43% reduction) and CAB (from 430 /100,000 to 337 /100,000; 22% reduction) p value < 0.0001 for all of them. Streptococcus pneumoniae was the most common pathogen in both periods, isolated in 258(46.6%) of cases. The relative proportion of S. pneumoniae decreased in the post-Prevnar period (from 60.9% to 35.5% P < 0.0001), while that of other pathogens increased, including Staphylococcus aureus (7.1% to 15.7%, P < 0.05) and Streptococcus pyogenes (3.4% to 6.9%, P < 0.05). The frequency of penicillin non-susceptible S. pneumoniae isolates decreased significantly (from 5.1% to 3.6%, P < 0.05). 86% (117/136) of the pneumococci isolated in the pre- prevnar period were PCV7 or PCV13 serotypes, compared with 50% (55/110) in the post- prevnar period. Meningitis was the final diagnosis in 31(5.6%) of patients, of them 18 (58.1%) were of pneumococcal meningitis,nine (50%) in the pre-Prevnar period. Overall mortality rate following CAB was 0.36%. Conclusion. we demonstrate that PCV reduces pediatric morbidity and hospitalization rate and impacts epidemiology of CAB. These changes may require change in the empiric antimicrobial treatment of suspected bacteremia. Continued etiological surveillance is important.