Article

Human Rhinovirus Species and Season of Infection Determine Illness Severity.

Pediatrics, University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin, United States.
American Journal of Respiratory and Critical Care Medicine (Impact Factor: 11.04). 08/2012; DOI: 10.1164/rccm.201202-0330OC
Source: PubMed

ABSTRACT RATIONALE: Human rhinoviruses (HRVs) consist of approximately 160 types that cause a wide range of clinical outcomes including asymptomatic infections, common colds, and severe lower respiratory illnesses. OBJECTIVE: To identify factors which influence the severity of HRV illnesses. METHODS: HRV species and types were determined in 1445 nasal lavages that were prospectively collected from 209 infants participating in a birth cohort who had at least one HRV infection. Questionnaires were used during each illness to identify moderate-to-severe illnesses (MSI). Measurements & MAIN RESULTS: Altogether, 670 HRV infections were identified and 519 of them were solitary infections (only one HRV type). These 519 viruses belonged to 93 different types of 3 species: 49 A, 9 B and 35 C. HRV-A (OR 8.2 [2.7, 25]) and HRV-C (OR 7.6 [2.6, 23]) were more likely to cause MSI compared to HRV-B. In addition, HRV infections were 5-10-fold more likely to cause MSI in the winter months (p<0.0001) compared to summer, in contrast to peak seasonal prevalence in spring and fall. When significant differences in host susceptibility to MSI (p=0.004) were considered, strain-specific rates of HRV MSI ranged from <1% to over 20%. CONCLUSIONS: Factors related to HRV species and type, season, and host susceptibility determine the risk of more severe HRV illness in infancy. These findings suggest that anti-HRV strategies should focus on HRV-A and -C species, and identify the need for additional studies to determine mechanisms for seasonal increases of HRV severity, independent of viral prevalence, in cold weather months.

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