Rhinovirus viremia in children with respiratory infections.

RATIONALE Viremia has been implicated in many viral infections; however, viremia due to rhinovirus (RV; rhinoviremia) has been considered not to occur in normal individuals. OBJECTIVE To evaluate whether RV enters the bloodstream and identify the possible risk factors. METHODS Nasopharyngeal washes (NPWs) of 221 children with respiratory infections were examined for the presence of RV by reverse transcription-polymerase chain reaction. Blood from 88 children, whose NPW was RV-positive, and 31 of RV-negative control subjects was subsequently examined for the presence of RV in the blood by semi-nested reverse transcription-polymerase chain reaction. Rhinoviremia was then correlated with clinical characteristics of the disease. RESULTS RV was detected in the blood of 10 out of 88 NPW RV-positive cases (11.4%): 7 of 28 children with asthma exacerbations (25.0%), 2 of 26 with common cold (7.7%), 1 of 25 with bronchiolitis (4.0%), and 0 of 9 with pneumonia (0%). All NPW RV-negative cases were negative in the blood. The proportion of rhinoviremia in children with asthma exacerbation was significantly higher compared with children suffering from the other diseases (25 vs. 5%, p = 0.01). Significant risk factors were: sampling <or= 24 hours from symptom initiation, personal history of asthma, and male sex. Age, fever, family, and personal history of atopy did not affect the presence of RV in the blood. CONCLUSIONS Viremia may occur during RV respiratory infections in normal children and is rather common in the early course of acute asthma exacerbations, suggesting that rhinoviremia may be involved in asthma exacerbation pathogenesis.