Risk of invasive pneumococcal disease in children and adults with asthma: A systematic review

Background: The Advisory Committee on Immunization Practices (ACIP) recommended the inclusion of asthma as a high-risk condition that should warrant pneumococcal vaccination, but the National Advisory Committee on Immunization (NACI) in Canada has not yet done so. We aimed to determine the risk of invasive pneumococcal disease (IPD) in patients with asthma. Methods: We searched Ovid Medline, EMBASE, Classic EMBASE, PubMEd and Cochrane for articles published between January 1990 and February 2013, using the MeSH terms pneumococcal infections/or invasive pneumococcal disease and asthma. Google Scholar was used to retrieve articles citing the seminal article by Talbot et al. Articles were included if they were population-based studies that evaluated the relationship between IPD and asthma. Two authors independently assessed all titles and abstracts. All potentially relevant articles were retrieved as full text and assessed for inclusion. Results: The combined searches yielded 376 articles, which were reviewed by title and abstract. At this stage, 330 articles were excluded; 40 articles were excluded at the full article review stage - leaving 6 articles. Two additional articles were found through Google Scholar. The evidence reviewed consistently showed a positive association between asthma and risk of IPD. However, the magnitude of this effect was heterogeneous with adjusted odds ratios ranging from 6.7 (95% CI 1.6-27.3) in adults >18 years to 1.7 (95% CI 0.99-3.0) in individuals aged 2-49 with low-risk asthma. Conclusion: The positive association between asthma and risk of IPD supports the addition of asthma as a high-risk condition warranting pneumococcal vaccination. Data on vaccine effectiveness in this population is needed. (C) 2013 Elsevier Ltd. All rights reserved.