The incidence of pneumococcal sepsis in children remained high after the introduction of the pneumococcal conjugate vaccine (PCV)-13 in Switzerland, according to a study published in Clinical Infectious Diseases. This study also found that meningitis from non-vaccine serotypes and disease caused specifically by serotype 3 were significant predictors of severity.       

Investigators assessed the effect of PCV vaccines on the burden of pneumococcal sepsis in children using a nationwide cohort from The Swiss Pediatric Sepsis Study. This cohort recruited children aged <17 years with Streptococcus pneumoniae blood culture-positive sepsis who also met the criteria for systemic inflammatory response syndrome between September 2011 and December 2015. Vaccine failure occurred if infection with a vaccine serotype developed in a child with up-to-date PCV immunization.

A total of 117 children with pneumococcal sepsis represented a crude incidence of 2.0 per 100,000 children (95% CI, 1.7-2.4) and 25% of community-acquired sepsis episodes. Approximately 25% of children (n=29) found to have meningitis were more often infected by non-vaccine serotypes (69% vs 31%; P <.001). Vaccine failure occurred in 16 of 62 children (26%) with up-to-date vaccinations; 11 of these children had infection with S pneumoniae serotype 3. The case fatality rate overall was 8%. The multivariable analyses found that children with meningitis (odds ratio [OR] 6.8; 95% CI, 2.4-19.3; P <.001) or with serotype 3 infection (OR 2.8; 95% CI, 1.1-7.3; P =.04) were more often admitted to the pediatric intensive care unit. The results also found that children with infection from serotype 3 had longer stays in the hospital (β coefficient 0.2, 95% CI, 0.1-1.1; P =.01).

The study benefited from a population-based design, prospectively collected data such as serotyping and vaccination status, and clearly defined criteria for the inclusion of children with bacteremia and systematic inflammatory response syndrome. This resulted in a population of patients with an unequivocal phenotype. Investigators noted that limitations refer to systematic inflammatory response syndrome-based sepsis definitions that were recently revised in the adult population. In addition, researchers were unable to report on the effect of PCV vaccination on the burden of pneumococcal sepsis in Switzerland as a result of a lack of data prior to the vaccine’s introduction.

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Investigators concluded that this work, “demonstrates the ongoing burden of pneumococcal sepsis among children in Switzerland, shortly after the introduction of PCV-13.” Further, according to investigators, data also supported the need for vaccines that better protect against serotype 3 and ongoing surveillance of invasive pneumococcal disease and sepsis.

Reference

Asner SA, Agyeman PKA, Gradoux E, et al. Burden of Streptococcus pneumoniae sepsis in children after introduction of pneumococcal conjugate vaccines – a prospective population-based cohort study [published online January 2, 2019]. Clin Infect Dis. doi: 10.1093/cid/ciy1139