Effectiveness of the 23-valent pneumococcal polysaccharide vaccine against invasive pneumococcal disease among 948,263 individuals ≥ 65 years of age: a Danish cohort study.
Katrine Finderup NielsenLise Birk NielsenFrederikke Kristensen LomholtSarah Kristine NørgaardHans-Christian SlotvedTine DalbyKurt FuurstedCharlotte Sværke JørgensenPalle Valentiner-BranthPublished in: European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology (2022)
This study aimed to estimate the effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPV23) against invasive pneumococcal disease (IPD) among individuals ≥ 65 years of age. We used Danish nationwide databases to obtain information on PPV23 vaccination, covariates, and IPD and linked data on an individual level using a unique personal identifier. A total of 948,263 individuals were included and followed between June 15, 2020, and September 18, 2021 (58.6% were vaccinated during follow-up). The adjusted vaccine effectiveness was 42% (95% confidence interval (CI): 9-63%) for all-serotype IPD and 58% (95% CI: 21-78%) for PPV23-serotype IPD, using no vaccination as the reference.