The impact of implementing the 10-valent pneumococcal conjugate vaccine on hospitalizations for pneumonia among children

Abstract

Pneumonia is a major cause of morbidity and mortality in children, with pneumococcus as the main etiologic agent. In Brazil, the 10-valent pneumococcal conjugate vaccine (PCV-10) was introduced into the childhood immunization schedule in 2010. The aim of this study was to assess the impact caused by implementing PCV-10 on the hospitalizations of children with pneumonia, between 2005 and 2015, in the state of Pernambuco, Brazil. An ecological time series study and a forecasting analysis were conducted. A comparison was made between the hospitalizations of children aged between seven months and four years due to pneumonia in the Brazilian Unified Health System, in the 5 years before (2005-2009) and after (2011-2015) implementation of PCV-10. Descriptive analysis included absolute and relative values, means and rates of hospitalization. The chi-square test was used to compare the annual incidence of hospitalizations and the t-Student test to compare the five-year mean values. For the temporal modeling of hospitalizations, an autoregressive integrated moving average was used, adjusted with seasonal-SARIMA (Box-Jenkins methodology), with a prediction of the monthly number of hospitalizations for 2011-2015. The predicted and observed values for 2011-2015 were then compared. The number of hospitalizations after implementing PCV-10 was reduced by 24.5 %. The monthly average of hospitalizations dropped from 681 (2005-2009) to 514 (2011-2015). The hospitalization rate dropped from 56.1 per thousand live births in the five-year period prior to PCV-10 to 43.4 in the following five-year period (a 22.7% reduction). Comparing the values predicted by the SARIMA model for a scenario without PCV-10 in the second five-year period, with those reported after implementing PCV-10, the estimated number of prevented hospitalizations was 8,682 in the five years following the introduction of the vaccine. In conclusion, in the five years following implementation of PCV-10, hospitalizations of children with pneumonia in Pernambuco decrease by 22%.

Keywords: Hospitalizations; Pneumococcal vaccines; Pneumonia; Time series.