Pneumococcal disease

Pneumococcal disease (PD) is infectious disease caused by Streptococcus pneumoniae (pneumococcus). PD is particularly common in younger children and in older adults and is roughly divided into invasive and non-invasive disease; the former refers to infections in which the microorganism is isolated from normal sterile body sites, such as the blood or the cerebrospinal fluid. Non-invasive PD can principally be divided into sinusitis, acute otitis media, and community-acquired pneumonia. S. pneumoniae remains the most common bacterial cause of community-acquired pneumonia. The invasive PD burden is mainly determined by pneumococcal meningitis, bacteremic pneumococcal pneumonia, and pneumococcal bacteremia without a primary focus. Incidence and mortality rates of both non-invasive and invasive disease have changed as a result of pneumococcal vaccination in children. However, especially elderly patients with comorbidities remain vulnerable to morbidity and mortality caused by PD.