Influence of pneumococcal vaccination on the hospitalization of healthy pediatric patients due to typical community-acquired pneumonia.

INTRODUCTION: Community-Acquired Pneumonia (CAP) is one of the most frequent causes of hospital admission in children. Our objective is to measure the impact of the introduction of pneumococcal conjugate vaccines on the hospitalization of previously healthy children due to CAP.

METHOD: From 2011-2016 a partially retrospective and prospective and descriptive study was carried out on healthy paediatric patients (3 months - 14 years old) with CAP, who required hospital admission. Clinical, epidemiological and demographic characteristics were collected and vaccination status was obtained from medical records.

RESULTS: A total of 292 cases were included, with a mean age of 33.4 months, 54% males. There was a progressive and significant 42% decrease in the number of admissions each year, without significant changes in the annual percentage of parapneumonic pleural effusion (PPE). The 56% of patients were immunized with a pneumococcal conjugate vaccine (PCV). The percentage of children who were not vaccinated decreased by 14% and the coverage with PCV13 increased by 46%. This revealed a significant increase of PPE in vaccinated patients with PCV-7 (63%) compared with unvaccinated (45%) and with PCV-13 (57%), without association to the presence of severe PPE. Moreover, no significant differences in severity or hospital stay were observed in unvaccinated patients, compared with those who were vaccinated. In >2 years old we observed a significant increase in PPE (59%) compared with 45% in younger children.

CONCLUSIONS: The increase in vaccination coverage with PCV-13 resulted in a decrease in hospitalizations due to CAP and PPE. Vaccination with PCV-7 is associated in our sample with an increase in PPE but not with severe PPE or an increase in hospital stay. There was an epidemiological shift of severe forms of pneumonia and empyema at later ages (> 2 yrs.).