Difference of the change of the hospitalization for pneumonia in children between Japanese secondary and tertiary medical facilities after the introduction of pneumococcal conjugate vaccine

This study aimed to compare hospitalization of children for pneumonia between secondary and tertiary medical facilities, which hospitalize many children without and with underlying diseases, respectively, after the introduction of the pneumococcal conjugate vaccine (PCV). Our retrospective study included children admitted to the Department of Pediatrics at Kitakyushu General Hospital, a secondary medical facility, and the Hospital of the University of Occupational and Environment Health, Japan, a tertiary medical facility, from 2009 to 2013 for pneumonia. We compared the change in the rate of hospitalization for pneumonia after the introduction of the 7-valent PCV between the secondary and tertiary medical facilities. Hospitalization of patients with pneumonia declined by 28.8% in our secondary medical facility. In particular, hospitalization for pneumonia other than confirmed mycoplasmal or viral pneumonia was significantly reduced by 49.2%. In contrast, hospitalization of patients with pneumonia did not decline in our tertiary medical facility. After the introduction of PCV, hospitalization of children for pneumonia was not reduced at the tertiary medical facility. Various other pathogens besides pneumococcus may be associated with the development of pneumonia in children with underlying diseases.