Estimation of the incidence of hospitalisation for non-invasive pneumococcal pneumonia in the Norwegian population aged 50 years and older

The purpose of this study was to estimate simple measures of the burden of non-invasive pneumococcal pneumonia (PnPn) hospitalisations in those aged 50 years and older (50+) in Norway. We conducted a retrospective register-based study and used discharge codes from the Norwegian Patient Register (NPR). We identified episodes of non-invasive PnPn in 2015 to 2016 and predicted its incidence from 2015 to 2019 based on the trend found in notified invasive pneumococcal disease cases. Overall, we identified 45–46 hospital episodes per 100 000 population of non-invasive PnPn in 2015 and 2016, each episode taking 6–8 days, and with increasing incidence with higher age. Among all identified PnPn episodes, 3 out of 4 were classified as non-invasive. We predicted that the monthly number of non-invasive PnPn episodes ranges from 39 [95% confidence interval (CI) 24–55] in August to 97 (95% CI 74–134) in December. No annual trend was identified. This study indicates that the burden of non-invasive PnPn hospitalisation has a substantial impact on the health and health care use of the 50+ population in Norway, despite the childhood immunisation programme. Many hospitalisations may be prevented through vaccination.