A Retrospective Study of Pneumococcal Pneumonia in Hospitalized Patients Aged ≥65 Years in Izumo, Japan: 2010 to 2014.

This study showed that the rate of in-hospital deaths due to pneumococcal pneumonia was halved after the PPSV23 vaccine was subsidized. The causal relationship between the pneumococcal vaccination rate and the mortality rate of pneumococcal disease was unclear. Further investigation is deemed necessary.