Assessment of the association between pediatric asthma and Streptococcus pyogenes upper respiratory infection

This study was designed to determine the relationship between asthma and the risk of developing Streptococcus pyogenes infections of the upper respiratory tract among children and adolescents. We conducted a retrospective cohort study that followed a convenience sample of 340 healthy children who participated in the Rochester Family Measles Study. Comprehensive medical record reviews determined asthma status by applying predetermined criteria. All laboratory test results of cultures, rapid antigen, and polymerase chain reaction tests for S. pyogenes infections during the first 18 years of life were collected to compare the incidence of S. pyogenes infections between asthmatic and nonasthmatic subjects. A Poisson regression was fit to determine the association between asthma and S. pyogenes infections controlling for other risk factors. Of the 340 subjects, we enrolled 327 who were eligible for this study. Of the 327 subjects, 114 (35%) had asthma. The incidences of S. pyogenes infections for asthmatic and nonasthmatic subjects were 0.25 per person-year and 0.18 per person-year, respectively. The adjusted risk ratio for asthma was 1.40 (95% CI, 1.12-1.74; p = 0.0029). Asthma in children is associated with an increased risk of S. pyogenes upper respiratory infections. The impact of asthma status on susceptibility to microbial infections needs to be considered in the context of a possible causal relationship between asthma and microbial infections. The mechanisms underlying this risk need to be elucidated.