Flu, Respiratory Syncytial Viruses Associated with Asthma Treatment Failures

Caroline Quatch, MD

Respiratory pathogens are a common trigger for pediatric asthma exacerbations, but a new study suggests that higher treatment failures are linked to particular infections.

Between 60-80% of pediatric asthma exacerbations are triggered by respiratory pathogens. For most children, the common cold is the culprit. But other viruses, such influenza, and some atypical bacteria, such as Mycoplasma pneumoniae, can also cause asthma exacerbations. However, little research has been done on the impact of specific pathogens.

This study found that asthmatics infected with the common cold virus (rhinovirus c) were more likely to experience successful treatment outcomes, but those infected with influenza, parainfluenza, and respiratory syncytial virus (RSV) did not respond as well and were at higher risk for relapse.

Researchers performed a secondary analysis of the Determinants of Oral Corticosteroid Responsiveness in Wheezing Asthmatic Youth (DOORWAY) study to explore the causes and treatment outcomes of specific infections. DOORWAY had shown that children diagnosed with both an acute asthma attack and viral respiratory infection had a higher risk of treatment failure.

Participants were between 1-17 years of age and admitted to the ER with moderate or severe asthma exacerbations. Nasopharyngeal samples were analyzed for 27 different respiratory pathogens. Researchers examined the associations between specific pathogens and both exacerbation severity and treatment failure (hospital admission, emergency room [ER] stay for longer than 8 hours, or relapse) using a standardized, severity-specific treatment.

Out of the 958 patients, 61.7% tested positive for a viral pathogen and 16.9% experienced treatment failure. The presence of a pathogen was associated with treatment failure (20.7% versus 12.5%; risk difference = 8.2% [95% CI; 3.3-13.1]) compared to the absence of a pathogen. Non-rhinovirus pathogens were associated with an increased risk of treatment failure by 13.1% (95% CI; 6.4-19.8); 8.8% for RSV, 24.9% for influenza, and 34.1% for parainfluenza.

Study co-author Caroline Quatch, MD, associate professor in the Department of Pediatrics, at McGill University Health Centre in Montreal, Canada, said the reasons why these viruses tend to decrease response to treatment are still not perfectly clear to clinicians.

“What is significant here is that influenza is the only viral infection that is vaccine-preventable,” Quatch said. “Although the influenza vaccine has, on average, 50-60% efficacy, it is the only way to prevent the illness and children with asthma should receive it yearly.”

Quach emphasized the importance to have accurate viral diagnosis so that future investigations can examine treatment efficacy stratified by virus type.

The study, "Respiratory Viruses and Treatment Failure in Children With Asthma Exacerbation," was published online in Pediatrics.