Rhinovirus Species in Acute Respiratory Tract Infections and the Risk of Asthma in Children.

BACKGROUND: Rhinoviruses (RV) are the most common pathogens causing respiratory tract infections, and early childhood RV wheezing illnesses are a known risk factor for childhood asthma. The role of acute upper respiratory tract infections (URTI) caused by different RV species in asthma development is not well known. METHODS: We conducted a nested case-control study in a birth cohort of 923 children followed prospectively from birth to age 7 years. Nasal swab samples collected during acute respiratory tract infections (ARI) at age 0-24 months were analyzed by PCR, and RV-positive samples were genotyped. Each case with asthma at age 7 years was matched with three cohort children without asthma. Conditional logistic regression was used to test associations between RV wheezing illnesses or RV URTIs and asthma risk. RESULTS: We identified 56 cases and 168 matched controls. In total, 807 RV-positive samples were successfully classified. Wheezing illnesses caused by RV-A and RV-C at age 0-24 months were associated with an increased risk of asthma at age 7 years (for RV-A, odds ratio [OR]: 1.60, 95% confidence interval [CI]: 1.05-2.43, p = 0.03; for RV-C, OR: 1.66, 95% CI: 1.11-2.49, p = 0.01). RV-A, RV-B, or RV-C positive URTIs were not associated with asthma risk. CONCLUSION: Both RV-A and RV-C -induced early wheezing illnesses were associated with an increased risk of childhood asthma. Acute URTIs caused by RV-A, RV-B, or RV-C were not associated with asthma risk.