Impact of pneumococcal conjugate vaccine on pneumonia hospitalization and mortality in children and elderly in Ecuador: time series analyses

Abstract

Background Pneumococcal conjugate vaccines (PCV) reduce the burden of invasive pneumococcal disease and pneumonia hospitalizations. However, there is limited evidence of the effect of PCVs on pneumonia mortality in children. It is anticipated that indirect effects resulting from PCV use among children might further reduce the remaining burden of adult pneumococcal disease caused by pneumococcal serotypes contained in PCV. Whether this will result in reduced pneumonia mortality in children and adults is still not known. Methods We investigated the impact of PCV on pneumonia hospitalization and mortality in in Ecuador, where PCV was introduced in 2010, considering national data from secondary data sources from 2005 to 2015. Time series analysis using regression models were used to evaluate the decline in the number of all-cause pneumonia hospitalizations and deaths in the period post-PCV introduction. The target populations were children under 5 years and adults aged 50 years and over. Outcomes of interest were hospitalizations and mortality in which the main cause of hospital admission and death, respectively, were coded as ICD10 codes J12-18 (pneumonia). Three different models were fitted. Results We demonstrate a sizeable impact of PCV in pneumonia hospitalization in children < 1 year (27% reduction, 95%CI 12–42%), and < 5 years of age (33% reduction, 95%CI 11–43%). The estimated impact of PCV in pneumonia mortality was a reduction of 14% in < 1 year (95%CI 0–33%), 10% in < 5 years (95%CI 0–25%), and 22% (95%CI 7–34%) in adults aged 50–64 years. Little evidence of a change was detected in elderly ≥ 65 years. Conclusion This study is the first to report on the impact of PCV in pneumonia morbidity and mortality in children and older adults, being relevant to policy makers and global donors. Findings were consistent when using different models. Additional studies on the indirect effect of PCV in older adults are needed.