Inés Iraola

Hospitalized children with pneumonia in Uruguay: Pre and post introduction of 7 and 13-valent pneumococcal conjugated vaccines into the National Immunization Program.

INTRODUCTION Streptococcus pneumoniae pneumonia burden in children was poorly defined in Uruguay. A three-year population-based surveillance demonstrated the impact of the pneumonia in hospitalized children of less than five years of age. To control these diseases in March 2008, Uruguayan health authorities decided to incorporate PCV7 to the National Immunization Program administered at 2, 4 and 12 months of age (2+1 schedule). OBJECTIVE To compare the incidence of consolidated pneumonia hospitalization in children less than five years of age before and after pneumococcal conjugate vaccine implementation. METHODS Same methodology of the prevaccination study was employed. The surveillance was carried out at the same four hospitals covering a population of 229,128 inhabitants (2004 Census) of whom 10.2% were under five years of age. Clinical data, vaccination status and digitization of their chest X-rays were recorded. A pediatric radiologist blinded to the clinical diagnosis interpreted the digital images according WHO definitions. Bacterial etiology was investigated in blood and/or in pleural fluid. RESULTS Between January 1st 2009 and June 30th 2011 patients were enrolled. Out of 23,445 children<5 years of age, 1224 were hospitalized with pneumonia (430 consolidated pneumonias and 794 non consolidated pneumonias). Pleural effusion was recorded in 89 patients. In 48 consolidated pneumonias S. pneumoniae etiology was recognized. Post vaccination incidence rate of consolidated pneumonia in patients aged 12-23 months showed a significant reduction (44.9%) if we compare it with the incidence of pneumonia hospitalization in the previous study. In March 2010, PCV13 replaced PCV7. Compliance of PCV7/13 globally was 92% but the vaccination status varied among the surveyed patients because two catch-ups were carried out in addition to the routine cohort vaccination. From 2009 1st semester to 2011 1st semester incidence rates decline reached 59%. CONCLUSION To date, the ongoing surveillance documented a significant decline on incidence of hospitalizations for consolidated pneumonia in children younger than 24 months of age, confirming the success of the 2+1 vaccination schedule.

Impact of Pneumococcal Conjugate Vaccines on the Incidence of Pneumonia in Hospitalized Children after Five Years of Its Introduction in Uruguay

Background Data on the burden of pneumococcal disease and the most frequent serotypes demonstrated that invasive disease and pneumonia were important manifestations affecting children under 5 years of age. Therefore, pneumococcal diseases prevention became a public health priority. Uruguay was the first Latin American country to incorporate PCV7 into its National Immunization Program. The aim of this study is to compare the incidence rates for hospitalized pneumonia in children from the pre PCV introduction period and the following five years of PCVs application in Uruguay. Methods and Findings Population-based surveillance of pneumonia hospitalization rates, in children, less than 14 years of age, had been performed prior pneumococcal vaccination, and continued following PCV7 introduction and PCV13 replacement, using the same methodology. Hospitalized children with pneumonia were enrolled from January 1, 2009 through December 31st, 2012. The study was carried out in an area with a population of 238,002 inhabitants of whom 18, 055 were under five years of age. Patients with acute lower respiratory infections for whom a chest radiograph was performed on admission were eligible. Digitalized radiographs were interpreted by a reference radiologist, using WHO criteria. Pneumonia was confirmed in 2,697 patients, 1,267 with consolidated and 1,430 with non consolidated pneumonia of which incidence decrease, between 2009 and 2012, was 27.3% and 46.4% respectively. 2001–2004 and 2009–2012 comparison showed a significant difference of 20.4% for consolidated pneumonia hospitalizations. A significant incidence decline was recorded among children 6 to 35 months of age. Conclusions An overall significant reduction in pneumonia hospitalizations was observed following the introduction of PCV7 and furthermore following the change to PCV13.

Pneumococcal Pneumonia in Hospitalized Uruguayan Children and Potential Prevention with Different Vaccine Formulations

OBJECTIVES To provide information on pneumococcal pneumonias, on their associated serotypes, and to estimate the coverage potentially afforded by antipneumococcal vaccines. STUDY DESIGN A retrospective study (2000 to 2004) was performed of patients with pneumococcal pneumonia aged 0 to 14 years admitted to the National Reference Childrens Hospital in Uruguay. Selected clinical data, radiographic interpretation, and microbiologic reports were obtained for analysis. RESULTS Of 410 enrolled patients, 384 had consolidated pneumonia/pleural effusion and 26 had infiltrates without consolidation: Pneumococcus was identified in blood or in pleural fluid of 387 patients; 21 serotypes were identified. The most frequent serotypes in decreasing order were serotypes 14, 1, 5, 3, 9V, 6B, and 7F. Forty-eight percent of invasive Streptococcus pneumoniae isolates were obtained from children younger than 24 months. For this group, the 7-valent vaccine would cover 60%, but a 10-valent vaccine would cover 83.8%. CONCLUSIONS This study provides information on pneumonia of proven S. pneumoniae causes and their associated serotypes, enabling estimation of potential effect of pneumococcal conjugate vaccines.