Association between human rhinovirus C and severity of acute asthma in children

Abstract

A new and potentially more pathogenic group of human rhinovirus (HRV), group C (HRVC), has recently been discovered. We hypothesised that HRVC would be present in children with acute asthma and cause more severe attacks than other viruses or HRV groups. Children with acute asthma (n = 128; age 2-16 yrs) were recruited on presentation to an emergency department. Asthma exacerbation severity was assessed, and respiratory viruses and HRV strains were identified in a nasal aspirate. The majority of the children studied had moderate-to-severe asthma (85.2%) and 98.9% were admitted to hospital. HRV was detected in 87.5% and other respiratory viruses in 14.8% of children, most of whom also had HRV. HRVC was present in the majority of children with acute asthma (59.4%) and associated with more severe asthma. Children with HRVC (n = 76) had higher asthma severity scores than children whose HRV infection was HRVA or HRVB only (n = 34; p = 0.018), and all other children (n = 50; p = 0.016). Of the 19 children with a non-HRV virus, 13 had HRV co-infections, seven of these being HRVC. HRVC accounts for the majority of asthma attacks in children presenting to hospital and causes more severe attacks than previously known HRV groups and other viruses.

Figure 1·0. Frequency of human rhinovirus (HRV) and other common respiratory viruses identified in 128 children with an asthma exacerbation

NB HRV strains were identified, hence children were categorized into those with new HRVC strains or those whose HRV infection was only with other HRV serotypes (HRVA or HRVB), two children had unidentified HRV infection. Other common respiratory viruses tested for were respiratory syncytial virus, adenovirus, influenza A and B, parainfluenza 1–4b, metapneumovirus, enterovirus, coronavirus, and bocavirus.

Figure 2·0. Relationship between human rhinovirus (HRV) C infection and severity of asthma exacerbation in 128 children

NB Following HRV strain identification in all but 2 cases, linear regression analyses showed that children with HRVC had significantly more severe asthma attacks than the children without HRVC (whether they were analysed as: (i) those whose HRV infection was only with HRVA or HRVB serotypes; (ii) those with any respiratory virus other than HRVC; or (iii) all children negative for HRVC). This boxplot shows the five statistics (minimum, first quartile, median, third quartile, and maximum) for exacerbation severity data.