Changes in Hospitalizations for Pneumonia After Universal Vaccination With Pneumococcal Conjugate Vaccines 7/13 Valent and Haemophilus influenzae Type b Conjugate Vaccine in a Pediatric Referral Hospital in Uruguay

Background: In 1994, Uruguay included Haemophilus influenzae b (Hib) conjugated vaccine in a 3 + 1 schedule. In March 2008, 7-valent pneumococcal conjugate vaccines (PCV7) was included in a 2 + 1 schedule. In 2010, 13-valent PCV replaced PCV7. Catch-up immunization was offered. The aim of this study was to describe the etiology of community-acquired pneumonia (CAP) in children 0-14 years of age hospitalized at the Hospital Pediatrico-Centro Hospitalario Pereira Rossell between 2003 and 2012. Methods: Annual hospitalization rates (per 10,000 discharges) for CAP and bacterial-confirmed CAP in children 0-14 years of age was described prior PCV7 vaccination (2003-2007), during the year of implementation of PCV7 (2008) and after the introduction of PCV7 (2009-2012). Data regarding age, strains isolated from pleural fluid and/or blood, vaccination status, pneumococcal and H. influenzae serotypes were obtained from Hospital Pediatrico-Centro Hospitalario Pereira Rossell databases and vaccination records. Results: Hospitalization rates for CAP and pneumococcal CAP between prevaccine years and the last year after introduction of vaccination with PCV (2012) significantly decreased by 78.1% and 92.4%, respectively. Significant reduction for 13-valent PCV vaccine serotypes and significant increase for nonvaccine serotypes was observed. A decrease in Staphylococcus aureus pneumonia was observed. Hospitalization rates for H. influenzae CAP remain stable before and after pneumococcal vaccination. Conclusions: Three years after PCV7/13 introduction into the routine vaccination schedule, there was a rapid and significant reduction in rates of CAP and P-CAP. An increase of etiology of CAP by other agents was not observed.