Impact of pneumococcal conjugate vaccines on selected head and neck infections in hospitalized israeli children

Background: Streptococcus pneumoniae is a major pathogen of pediatric head and neck infections (HNIs), for example, acute otitis media (AOM), acute mastoiditis, acute bacterial sinusitis and meningitis. The aim of this study was to characterize the epidemiology of pneumococcal HNIs (pHNIs) before, during and after the introduction of pneumococcal conjugate vaccines (PCVs). Methods: Children 0-16 years of age, who were hospitalized with HNIs in the pediatrics department in a general hospital between January 1, 2007, and December 31, 2014, were retrospectively identified. Study years were categorized according to the PCV introduction timeline: 2007-2008: "pre-PCV years"; 2009-2011: "transition years" and 2012-2014: "post-PCV years." pHNIs episodes were defined if pneumococcal culture or urine antigen was positive. Children who received ≥2 doses of PCV7/PCV13 were considered as immunized. All other children were considered as unimmunized. Results: HNIs accounted for 2.5%-4.7% of the total admissions; 3%-17% of them were pHNIs. Eighty-seven pHNI episodes were identified: AOM (n = 42), acute mastoiditis (n = 28) and meningitis (n = 17). There was a downward trend in the overall incidence of HNIs, and particularly of pHNIs, in the post-PCV years. The average age and hospitalization duration of children with HNIs/pHNIs remained stable during the study years. In 2009-2010, pHNIs incidence sharply decreased, from 7 to 1.74/1000 hospitalized children/year, due to ∼55% reduction of pneumococcal AOM episodes. An additional decrease was observed in the post-PCV years (1.62/1000 hospitalized children/year). Immunized children were less likely to present with pHNIs (P = 0.001) but were more likely to undergo surgery (P = 0.042). Conclusion: We observed a reduction in pHNIs incidence after PCV program implementation.