Asthma increases risk of whooping cough
Published Online: December 30, 2011
Bordetella pertussis is a bacterium that causes whooping cough (pertussis), a serious respiratory infection affecting a large number of people worldwide. The recent outbreak of pertussis in California in 2010, during which 9,143 pertussis cases were reported to the California Department of Public Health and this recent outbreak, emphasizes that pertussis remains a major threat to public health in the U.S. It had previously been unknown whether asthma status poses an increased risk of pertussis.
Capili et al reports in a recent issue of The Journal of Allergy and Clinical Immunology (JACI) that patients (both adults and children) with asthma are at an increased risk of developing whooping cough caused by Bordetella pertussis, compared to those without asthma. They conducted a population-based case-control study in Olmsted County, Minnesota, during the pertussis outbreak between 2004 and 2005, which included 164 lab-test proven pertussis cases and 328 age- and gender-matched controls.
They found that the odds of whooping cough among patients with asthma was 1.7 times higher than among those without asthma, suggesting that asthma significantly increased risk for whooping cough. Based on their results, they estimated that 17% of the burden of whooping cough could be attributed to asthma at a population level. They postulate that waning of anti-pertussis immunity might play a role in the increased risk of whooping cough and that asthmatics might have a more rapid waning of anti-pertussis immunity than normal individuals. The mechanisms underlying this increased risk of whooping cough among individuals with asthma require further study.
In the meantime, given the major outbreak of pertussis in the US, the significant risk of pertussis among asthmatics, and a significant number of Americans affected by asthma, consideration of replacing decennial Td booster with Tdap including acellular pertussis vaccine should be given in individuals with asthma. Immune surveillance for pertussis in asthmatics as a selective risk group should be also considered.
The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.