Adult invasive pneumococcal disease in the Republic of Korea: Risk medical conditions and mortality stratified by age group

Objectives: This study aimed to characterize the risk factors for mortality in adult patients with invasive pneumococcal disease (IPD) stratified by age groups, after implementation of the national immunization program of 23-valent polysaccharide vaccine (PPSV23) for those aged ≥65 years in the Republic of Korea (ROK). Methods: Clinical data and pneumococcal isolates from adult patients with IPD (≥18 years of age) were collected prospectively from 20 hospitals through the nationwide surveillance program from March 2013 to October 2015. Results: A total of 319 patients with IPD were enrolled. Median age was 69 years. Overall in-hospital mortality was 34.2%: 17.1% in those aged 18–49 years, 23.7% in those aged 50–64 years, 33.0% in those aged 65–74 years, and 51.0% in those aged ≥75 years (p