Asthma and Invasive Pneumococcal Infections
Talbot RT, Hartert TV Mitchel E, et al. Asthma as a risk factor for invasive pneumococcal disease. N Engl J Med. 2005; 352: 2082-90.
Current guidelines for pneumococcal vaccination exclude people with asthma, nor do the most recently published guidelines for management of asthma include pneumococcal vaccination. The authors of this study utilized public health databases to perform a nested case-controlled cohort study to determine the risk of pneumococcal disease among people with asthma. By combining a database of active surveillance for invasive pneumococcal disease (IPD) with a state-based managed healthcare program, researchers identified 635 cases of IPD in people with asthma and paired them with 6,350 age-matched controls. The age range of test subjects was 2 to 49 years (mean, 28.5). After adjustment for race and other conditions with high risk for IPD, asthma was significantly associated with increased risk of IPD (OR: 2.4; 95% CI: 1.9 to 3.1). This finding was consistent in analyses stratified for age (2 to 4 years and 5 to 17 years). Of the isolates causing IPD, 56.9% were among the 7 serotypes included in the pneumococcal conjugate vaccine, with an additional 29.1% found only in the 23-valent polysaccharide vaccine. The authors hypothesize that obstruction caused by increased production and decreased clearance of mucus and the chronic airway inflammation found in asthma are plausible etiologies for the increased risk of IPD. They conclude that consideration should be given for the addition of asthma to the list of conditions warranting pneumococcal vaccination, particularly for the younger population in the study, who are less likely to have other high-risk conditions for which vaccination is already recommended.