The impact of 10-valent pneumococcal conjugate vaccine upon hospitalization rate of children with pneumonia in different Brazilian administrative regions

Abstract

Background: Streptococcus pneumoniae is the most frequent bacterial causative agent of pneumonia. Due to its significant contribution to the morbidity and mortality profile and the country's economy, the 10-valent pneumococcal vaccine (PCV10) was introduced in Brazil in 2010. Brazil is divided into five administrative regions which differ in social-economic indices among each other. Estimates of PCV10 impact on hospitalization rates due to pneumonia stratified by distinct Brazilian regions are limited. We assessed this issue.

Methods: This is a population-based ecological investigation. Data about hospitalizations due to pneumonia, asthma or urinary tract infection (UTI) among patients aged under 20 years in the pre-exposure (2003-2009) and in the post-exposure (2011-2017) periods were retrieved from the National Health System - Hospital Information System (SIH-SUS) database. The total resident population by age group in each year was retrieved from the Brazilian Institute for Geography and Statistics database. Hospitalization rates were estimated for each Brazilian region and the rates obtained in the pre-exposure and in the post-exposure periods were compared by Prais-Winsten regression. The Human Development Index (HDI) evolved differently in the distinct regions during the study period.

Results: Overall, hospitalization rates due to pneumonia declined by 34.5%. Similar trends were observed for hospitalization rates due to asthma and UTI. The same pattern was observed in each Brazilian region. However, the North region was the only one that presented an exponential incidence decline pattern, which could be explained by PCV10 implementation (declined by 10.8% in the quadratic regression, p < 0.01). Only in the North region, significant decline was observed among patients aged 0-4 years (-12.5%; p = 0.01), 5-9 years (-38.5%; p < 0.01) or 10-14 years (-10.7%; p = 0.03).

Conclusion: Significant variation in the downward trend of hospitalization rate was only found in the North region, which evolved from very low HDI in 2003; medium HDI in 2010 to high HDI in 2017.

Keywords: Children; Hospitalization; Pneumococcal pneumonia; Vaccination.