Wheezing Due to Rhinovirus Could Set the Stage for Asthma Development

Researchers conducted a meta-analysis of the existing literature regarding links between rhinovirus (RV) wheezing and the development of childhood asthma and found that there is an association; children who wheeze due to RV during the first 3 years of life are more likely to develop asthma. Lu Liu, of the Department of Respiratory and Critical Care Medicine at the First Affiliated Hospital of Xi’an Jiaotong University in China and colleagues conducted the analysis.

Experts have suspected the possibility of an association between RV and the later development of asthma for some time, but there is no clear evidence, and there is some debate among the scientific community. The reviewers suggest that finding evidence of an association, as well as developing an understanding of the association, could inform the treatment of childhood asthma.

The reviewers searched PubMed, EMBASE, Web of Science, the Chinese National Knowledge Infrastructure (CNKI), and the Wanfang databases to find the studies included in the meta-analysis. To be included, the studies had to be original, include children no older than 3 years of age who had been diagnosed with RV that had been virologically confirmed, included a follow-up period, and included the outcome of interest, which was wheezing or asthma.

A total of 15 studies met the inclusion criteria, although the reviewers originally identified 6504. “All selected studies are cohort studies and in children under 3 years of age, with confirmed RV-associated wheezing and a defined outcome (later childhood wheezing/asthma),” the authors reported, adding that 10 of the studies report the results of 4 longitudinal studies with different follow-up periods.

The reviewers note that there have been previous analyses, but they have been simple and descriptive in nature and did not include all relevant studies. “In the present meta-analysis,” they said, “we combined eligible studies to yield summary results, which indicated that RV wheezing illness in the first 3 years was associated with subsequent development of wheezing/asthma in overall analysis.”

Further analysis showed that the association between RV wheezing and asthma-related wheezing remains significant up to the age of 10 years, but not always after that. However, they caution that one problem with cohort studies is confounding factors, which can lead to biased results. Additional findings related to the mechanisms underlying the association between RV wheezing and asthma wheezing include increased airway sensitization from RV infection, the release of novel innate cytokines, and the upregulation of the expression of genes that increase susceptibility to asthma.

“Effective strategies against RV could prevent the development of early-life RV wheezing illness as well as attenuate the consequences of the immune response to the pathogen, which may reduce asthma risk,” the authors said. However, at the current time, treatments for RV are not widely available because there are many subtypes of RV, leading the authors to advocate for more studies into RV species and development of effective interventions.

Some limitations exist regarding this review. For example, there were relatively few studies with relatively few participants included, RV is difficult to culture and, therefore, difficult to diagnose, wheezing is not always diagnosed by a physician, which could be problematic, as well as some other factors. However, even taking those limitations into account, the authors suggest the results of the present review indicate a need for “more large-size prospective studies.”

The study, “Association between Rhinovirus Wheezing Illness and the Development of Childhood Asthma: a Meta-analysis,” can be found in BMJ Open.

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