Expanded Analysis of 20 Pneumococcal Serotypes Associated With Radiographically Confirmed Community-Acquired Pneumonia in Hospitalized US Adults.

Background Streptococcus pneumoniae is a causative agent of community-acquired pneumonia (CAP). The 13-valent pneumococcal conjugate vaccine (PCV13) has significantly decreased the burden of PCV13-serotype pneumococcal disease; however, disease due to nonvaccine serotypes remains substantial. A recent study documented the persistence of PCV13 serotypes among US adults hospitalized with radiographically confirmed CAP. The current analysis used a recently developed urinary antigen detection (UAD) assay (UAD2) to extend these results to additional serotypes included in an investigational PCV20 vaccine. Methods This prospective study enrolled adults aged ≥18 years hospitalized with radiographically confirmed CAP between October 2013-September 2016. Presence of S pneumoniae was determined by blood and respiratory sample culture, BinaxNOW® urine testing, and UAD. In addition to Quellung on cultured isolates when available, serotypes were identified from urine specimens using UAD1 for PCV13 serotypes and UAD2 for 7 PCV20-unique serotypes (8, 10A, 11A, 12F, 15B, 22F, and 33F) and 4 additional serotypes (2, 9N, 17F, and 20). Results Among 12,055 subjects with radiographically confirmed CAP, 1482 were positive for S pneumoniae. PCV13 and PCV20-unique serotypes were associated with 37.7% (n=559) and 27.0% (n=400) of cases, respectively; 288 subjects were exclusively diagnosed as positive for S pneumoniae by UAD2. Demographic and clinical disease characteristics were similar between subjects with CAP caused by PCV13 and PCV20-unique serotypes. Conclusions The current analysis using UAD2 identified a sizeable proportion of hospitalized adult CAP associated with PCV20-unique serotypes. PCV20 may therefore address the burden of CAP caused by the additional serotypes present in the vaccine.