Abstract Rationale From the national report in Japan, the number of Invasive pneumococcal diseases (IPDs) were reported 3348 patients in 2019, however, decreased in 1654 patients in 2020. These data suggested that COVID-19 pandemic from 2020 to 2023 affected the incidence of severe pneumococcal pneumonia, including IPDs. Methods We investigated the number of the IPD cases in our hospital from 2020 to 2023, and compared the cases in pre-/post- COVID-19 period, such as in 2019, 2024, and 2025. Furthermore, the clinical features of the non-survived cases were compared with survived cases. Results During the COVID-19 pandemic from 2020 to 2023 in Japan, we had seven IPD cases although 14 IPD cases were treated in 2019, 2024, and 2025 in our hospital. Among total 21 IPDs patients, five patients (23.8%) were dead, and all these non-survived cases were treated in 2019, 2024, and 2025. Furthermore, non-survived patients were younger (54.0vs 69.4 years old, p = 0.0011), and showed lower white blood cell counts (3672.1 vs 12117.3/µL, p = 0.0011) and higher C-reactive protein (34.5 vs 22.1 mg/dL, p = 0.0010), compared with survived patients. Two or more bacteria were isolated and multiple antimicrobial agents were used in non-survived patients, rather than survived patients. Conclusions These data suggested that severe pneumococcal pneumonia cases decreased and might be less pathogenic during COVID-19 pandemic period, compared with the cases in pre- and post- COVID-19 pandemic period. In addition, non-survived patients were younger and showed higher inflammation due to multiple bacterial infection, compared with survived patients. This abstract is funded by: None
M Seki (Fri,) studied this question.