Flu in kids is associated with asthma treatment failure

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Upper respiratory illnesses caused by influenza viruses can trigger asthmatic episodes that don't respond to treatment in kids, new research in Pediatrics finds.

Today's study assessed close to 1,000 children treated for moderate or severe asthma attacks in emergency rooms in the Montreal Children's Hospital and three other Canadian hospitals from 2011 through 2013.

Study co-author Caroline Quach, MD, an associate professor of microbiology and infectious diseases at the University of Montreal and chair of the National Advisory Committee on Immunization of the Public Health Agency of Canada, explained that research had shown a connection between viral infections and children failing typical asthma treatment, but it wasn't known how or if the risk differed among viruses.

"We were happy to see that children infected with rhinovirus responded as well to asthma treatment as others," Quach told CIDRAP News. Rhinoviruses are to blame for the common cold, and are far more prevalent than influenza viruses. "However, those infected with influenza, parainfluenza, and RSV [respiratory syncytial virus] had more risk of failing therapy."

To conduct the study, researchers swabbed the nasal passages of children when they came in for treatment, and 61.7% of study participants had an upper respiratory infection. According to the study, non-rhinovirus pathogens were associated with an increased risk of treatment failure by 13.1% (95% confidence interval: 6.4% to 19.8%). When broken down by pathogen, the increased risk was 8.8% for RSV, 24.9% for influenza, and 34.1% for parainfluenza. 

"The reasons why these viruses tend to decrease response to treatment are not entirely clear," Quach said. What is clear, however, is that the influenza vaccine is one simple tool to offer asthmatic kids.

"Influenza is the only respiratory virus that is vaccine-preventable," Quach said in a press release from the University of Montreal. "Granted, it's at best only 50% efficacious, but that's no reason for kids with asthma not to get vaccinated yearly, in the fall, before flu season starts."

Importance of flu vaccine

In Canada, annual flu vaccination is recommended for kids with asthma, but only about 60% comply with the recommendation, often because parents report a burden to accessing the vaccine at public health clinics.

Quach showed in a 2016 study that offering the flu vaccine to pediatric patients at tertiary care hospitals is one easy way to reach more children.

"Given the documented safety of influenza immunization in children with asthma and its expected protective effect, it appears reasonable to pursue strategies to improve immunization coverage for influenza and invest in efforts for the development of vaccines for RSV and rhinovirus," the study concluded.

See also

Jun 4 Pediatric study

Jun 4 University of Montreal press release

Feb 2016 Vaccine study

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