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

Laurani H (2014) Impact of Pneumococcal Conjugate Vaccines on the Incidence of Pneumonia in Hospitalized Children after Five Years of Its Introduction in Uruguay. PLoS ONE 9(6): e98567. doi:10.1371/journal.pone.0098567 Impact of Pneumococcal Conjugate Vaccines on the Incidence of Pneumonia in Hospitalized Children after Five Years of Its Introduction in Uruguay Mara Hortal 0 Miguel Estevan 0 Miguel Meny 0 Ine s Iraola 0 Hilda Laurani 0 Bernard Beall, Centers for Disease Control & Prevention, United States of America 0 1 Basic Sciences Development, National University , Montevideo , Uruguay , 2 Radiology Department, Children's Hospital, Ministry of Health , Montevideo , Uruguay , 3 Statistics Department, Montevideo Municipality, Uruguay, 4 Pediatric Department, Social Security , Montevideo, Uruguay, 5 Immunization Department, CHLAP, Montevideo , 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. - Streptococcu pneumoniae is an important cause of severe morbidity and mortality among the pediatric population. Following efficacy studies, the heptavalent pneumococcal conjugate vaccine (PCV7) was approved for use in the pediatric population in 2000. It was introduced into National Immunization Programs (NIPs) globally, in order to control pneumococcal diseases in the most vulnerable age groups, particularly those less than 24 months of age. PCV7 effectiveness was demonstrated for the prevention of vaccine type pneumococcal diseases, as well as, for all cause pneumonia and otitis media.Despite its effectiveness, expanding serotype coverage led to the introduction of PCVs with more serotypes. PCV13, which contains the 7 original serotypes and six additional serotypes all conjugated to the carrier protein, CRM197, approved in 2010. Data on the burden of pneumococcal disease, and the most frequent serotypes involved, demonstrated that invasive disease, as well as, pneumonia were the most important manifestations affecting Latin American children less that 5 years of age [13]. Uruguay was the first Latin American country to incorporate PCV7 into its NIP in a 2+1 dosing schedule. PCV7 was incorporated in March 2008, with doses given at 2, 4 and 12 months of age, for the 2008 birth cohort, and a catch-up program of 2 doses, at 15 and 17 months of age, was given to the 2007 birth cohort. In March 2010, PCV13 replaced PCV7, with the same dosing schedule, and a catch-up was offered to children up to 5 years of age. Population-based surveillance of pneumonia hospitalization rates in children less than a month to 14 years of age, had been performed prior to initiation of PCV7 vaccination, and continued following the introduction of PCV7 and PCV13, using the same methodology [4, 5]. The aim of this study is to compare the incidence rates for hospitalized pneumonia in children from the Non Consolidated Pneumonia *Incidence is calculated by 100,000 person-year. doi:10.1371/journal.pone.0098567.t001 pre PCV introduction period, and the following five years of its application in Uruguay. This population-based surveillance, enrolled hospitalized children with community-acquired pneumonia, from January 1, 2009 through December 31st, 2012. The (...truncated)