A test-negative case-control study used 34,009 adult pneumonia hospitalisations in the US Veterans Affairs system from January 2023 to December 2025, of which 837 (2.5%) were culture-positive for Streptococcus pneumoniae and 21.8% of patients had received PCV20. Estimated effectiveness against culture-confirmed pneumococcal pneumonia hospitalisation was 20.4% (95% CI 2.1–35.3) at ages 65 and over and 8.8% (95% CI −8.8 to 23.6) across all adults, with the highest estimate in the Western region (39.6%). Results were consistent under inverse probability weighting.
Why it is interesting: One of the first real-world effectiveness estimates for PCV20 against pneumococcal pneumonia admissions, and the point estimates are modest and regionally uneven.