Role of Rhinovirus C Respiratory Infections in Sick and Healthy Children in Spain

Background: Recently a new genogroup of human rhinovirus (HRV) has been described and named HRV-C. The relative importance of HRV-C in viral respiratory tract illnesses is unknown. Objective: We looked for HRV-C in pediatric patients with respiratory tract infections to determine the incidence of HRV-C and its role in sick and healthy children. We describe the clinical differences associated with HRV-C infections and other HRV genogroups. Patients and Methods: From January 2004 to December 2008, a prospective study was conducted in children younger than 14 years who were admitted with respiratory infection to the Pediatrics Department of the Severo Ochoa Hospital in Madrid, Spain. Specimens of nasopharyngeal aspirate were taken for virologic study with polymerase chain reaction, and clinical data were recorded. HRV specimens were genotyped. We studied the frequency of HRV-C infections, the clinical course of these patients and the differences with other HRV genogroups (HRV-A and HRV-B). Presence of HRV-C was also studied in a group of healthy children. Results: HRV was detected in 424 of 1555 episodes of illness (27.2%) and in 26 of 211 healthy children (12.3%) (P < 0.001). We amplified at random 248 of them (227 hospitalized children and 21 healthy children): 132 (53.2%) had HRV-A, 28 (11.2%) had HRV-B, and 88 (35.4%) HRV-C. HRV-C infections were associated with asthma, recurrent wheezing, and bronchiolitis but were not significantly different from the HRV-A genogroup. Nevertheless, significant clinical differences were observed between the HRV-B genogroup and the other groups: more frequent infiltrate on chest radiograph (P = 0.017), fever (P = 0.052), diagnosis of pneumonia (P = 0.01), and antibiotic treatment (P = 0.004). Conclusions: HRV-C infections were frequent in hospitalized children with respiratory diseases and were associated with asthma, recurrent wheezing, and bronchiolitis. No clinical differences were found with the HRV-A group: HRV-B group had clinical differences with both the other groups.