Trends and Surveillance of Adult Pneumococcal Diseases in Arkansas State, 2000 to 2013.

Abstract

Pneumococcal diseases have high mortality and morbidity worldwide, and they present in two major clinical manifestations: 1) pneumococcal pneumonia, which is the most common manifestation and 2) invasive pneumococcal disease that is less frequent but more often fatal. Pneumococcal diseases disproportionately affect young children and the elderly. The population of Arkansas is highly vulnerable due to high rates of chronic diseases, a rapidly aging population and low adult vaccinations rates. This dissertation aims at understanding the epidemiology of adult pneumococcal pneumonia and adult invasive pneumococcal disease in the state of Arkansas during the past 14 years to inform future immunization program improvement. Additionally, the sensitivity and completeness of the adult invasive pneumococcal disease surveillance system during 2003 to 2013 were assessed to evaluate the usefulness of surveillance data in informing immunization planning. Records of adult pneumococcal pneumonia and invasive pneumococcal disease cases with de-identified demographic information were extracted from hospital discharge data. Overall and subpopulation trends were evaluated using generalized linear models. Pneumococcal pneumonia trends displayed a gradual annual percent decline of 5.07% per year (95% CI: 3.53, 6.95) from 2000 to 2009. The decline became more pronounced from 2010 to 2013 at 19.10% per year (95% CI: 14.10, 23.51). On the other hand, the IPD trends showed a small annual percent increment of 3.66% per year (95% CI: 2.02, 4.92) from 2000 to 2009, followed by a decline of 11.31% per year (95% CI: 15.46, 6.57) from 2010 to 2013. Subpopulation trends showed similar trend patterns. These results highlight the indirect effects of the introduction of childhood vaccinations PCV7 in 2000 and PCV13 in 2010 on the reduction of the pneumococcal disease burden among adults. The surveillance system assessment revealed its low capacity for capturing adult invasive pneumococcal disease cases. However, a significant improvement in the sensitivity and data quality was observed over time, especially after the implementation of the web-based National Electronic Disease Surveillance System.