Epidemiologic, clinical, and virologic characteristics of human rhinovirus infection among otherwise healthy children and adults: rhinovirus among adults and children

Abstract

Background: human rhinovirus (HRV) is a major cause of influenza-like illness (ILI) in adults and children. Differences in disease severity by HRV species have been described among hospitalized patients with underlying illness. Less is known about the clinical and virologic characteristics of HRV infection among otherwise healthy populations, particularly adults.

Objectives: to characterize molecular epidemiology of HRV and association between HRV species and clinical presentation and viral shedding.

Study design: observational, prospective, facility-based study of ILI was conducted from February 2010 to April 2012. Collection of nasopharyngeal specimens, patient symptoms, and clinical information occurred on days 0, 3, 7, and 28. Patients recorded symptom severity daily for the first 7 days of illness in a symptom diary. HRV was identified by RT-PCR and genotyped for species determination. Cases who were co-infected with other viral respiratory pathogens were excluded from the analysis. We evaluated the associations between HRV species, clinical severity, and patterns of viral shedding.

Results: eighty-four HRV cases were identified and their isolates genotyped. Of these, 62 (74%) were >18 years. Fifty-four were HRV-A, 11HRV-B, and 19HRV-C. HRV-C infection was more common among children than adults (59% vs. 10%, P<0.001). Among adults, HRV-A was associated with higher severity of upper respiratory symptoms compared to HRV-B (P=0.02), but no such association was found in children. In addition, adults shed HRV-A significantly longer than HRV-C (P trend=0.01).

Conclusions: among otherwise healthy adults with HRV infection, we observed species-specific differences in respiratory symptom severity and duration of viral shedding.

Keywords: HRV genotypes; Military; Rhinovirus; Viral shedding.

Fig. 2

Phylogenetic tree of partial HRV VP4/VP2 RNA sequences from 84 study samples. Prototype strains of HRV-A–C from GenBank were included for comparison (Clustal X version 2.0.1). The tree was constructed using the neighbor-joining method in MEGA software (version 5). The statistical significance of the tree topology was tested by bootstrapping (1000 replicas). Pairwise distances between and within the genotypes at the nucleotide level were calculated with Kimura 2 parameters and with Poisson correction at the amino acid level with MEGA software. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) Black dot: hospitalized case, sequence name in red: standard sequence, Cox: coxsackievirus.

Fig. 1

Proportion of HRV species, by age group. Black bar: children, white bar: adults. Note: *P-value of chi-square test on the proportion of patients with HRV-C infection between children and adults.

Fig. 3

Median and interquartile range of composite symptom scores among adults, by HRV genotypes. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) Red solid line: HRV-A; blue dashed line: HRV-B; green dotted line: HRV-C. **P ≤ 0.05, *P > 0.05 & P ≤ 0.1 for comparison across three HRV genotypes.