Human Rhinovirus C Infection in 21-Year Prospective Cohort of Children with Upper and Lower Respiratory Tract Illness

RATIONALE: The role of human rhinovirus C (HRV-C) as compared to HRV A and B in upper and lower respiratory disease in young children is poorly understood. METHODS: We tested nasal-wash specimens obtained from otherwise healthy children presenting with acute respiratory tract illness or otitis media between 1982 and 2003 in Nashville, Tennessee for HRV with real-time RT-PCR. To determine the HRV species, we sequenced the VP4/VP2 gene from HRV-positive specimens. RESULTS: Of 548 samples tested, 200 (36.5%) were positive for HRV. Of the 200 HRV-positive samples, 46% were HRV-A, 2.5% were HRV-B, 34% were HRV-C, and 16% were untypable. Of all HRV-positive samples, 69.2% were associated with upper-respiratory illness (URI), and 22.6% were associated with lower-respiratory illness (LRI). Of all 379 URI samples, 38.5% were HRV-positive. Of the 124 LRI samples, 43.5% were HRV-positive. There was not a significant difference in the proportion of HRV-A vs HRV-C among patients with HRV-positive URI vs LRI (HRV-A: 38.5% URI vs 30% LRI, HRV-C: 41% URI vs 50% LRI, p = 0.2). Seasonality and prevalence of each HRV group varied year to year. CONCLUSIONS: Human rhinovirus C has been associated with a significant proportion of upper and lower respiratory illness in children during the past 21 years and is likely a large contributor to the increased burden of HRV identified by RT-PCR compared to culture alone. There are similar proportions of HRV-C in children with URI vs LRI. Studies in multiple locations and over multiple years are required to better understand these viruses.