Protecting against invasive pneumococcal disease: be wise--immunize

Invasive pneumococcal disease is characterized by the detection of S. pneumoniae from a normally sterile site (e.g., blood, cerebrospinal fluid or pleural fluid);4 the name does not imply any measure of severity of illness. Each year in Canada, pneumococcal disease is responsible for an estimated 3000 cases of invasive pneumonia, 750 cases of bacteremia and 240 cases of meningitis.2 People with pneumococcal pneumonia often present with high fever and chills of abrupt onset, accompanied by chest pain and productive cough, with rust-coloured, mucopurulent sputum. Pneumococcal meningitis is often preceded by pulmonary or mild upper respiratory tract infection. Pneumococcal bacteremia is a complication in 25% of cases of S. pneumoniae pneumonia and 80% of cases of S. pneumoniae meningitis.4 The mortality rates for invasive pneumococcal disease are surprisingly high. Among people with coexisting chronic disease, case fatality rates are estimated at 15% for those under 65 years of age and 30% for those 65 years of age and older.5 Among people with no risk factors, the case fatality rate is 5.6%.(5)