- Increasing prevalence of pleural empyema (PE) complicating community acquired pneumonia (CAP) is reported worldwide. We compared hospitalized children with PE or non-purulent pleural effusion (NP-PEF) prior to the inclusion of the pneumococcal conjugated vaccine (PCV7) in the Israeli immunization schedule. We conducted a retrospective analysis of medical files of all children <18 y of age hospitalized with either PE or NP-PEF and CAP during 1990-2002. 75 children with NP-PEF and 37 with PE were identified. PE annual incidence increased from 0.5 in 1990 to 4.2 per 100,000 children in 2002. Higher WBC and absolute neutrophils counts were found in sera and pleural fluid of PE. The leading pathogens included Streptococcus pneumoniae (42%, all penicillin-susceptible) and Staphylococcus aureus (23%, all methicillin-susceptible). Blood cultures were positive only in children with PE (12/37, 32.4%). Patients with PE presented with higher respiratory rate and required longer hospitalization, more PICU admission, and more patients needed mechanical ventilation. PE prevalence increased in southern Israel during the study period. Streptococcus pneumoniae (62.5% serotype 1) was the most common pathogen causing PE before the introduction of PCV7. Future introduction of PCV7 or equivalents in the immunization schedule may impact clinical presentation and epidemic trends and will require future consideration.