Antiviral treatment is largely underused in children with influenza, study findings show

 Despite national medical guidelines supporting the use of antiviral medications in young children diagnosed with influenza, a new study reports an underuse of the treatment.

"Trends in Outpatient Influenza Antiviral Use Among Children and Adolescents in the United States" was published in Pediatrics, a peer-reviewed journal of the American Academy of Pediatrics.

"Antiviral treatment, when used early, improves health outcomes with influenza," said lead author and principal investigator James Antoon, MD, PhD, MPH, assistant professor of Pediatrics and Hospital Medicine at Monroe Carell Jr. Children's Hospital at Vanderbilt.

Antoon and colleagues collaborated with researchers from the University of Illinois at Chicago on a large study examining outpatient and emergency department prescription claims for patients younger than 18 from all 50 states over a nine-year period.

Oseltamivir, also known at Tamiflu, is the only oral antiviral medication approved for use in children younger than 5 years old.

"We found that young children, less than 5 years old and especially those 2 years old and younger, are undertreated for influenza," said Antoon. "We noted that about 40% of children were treated with an antiviral, when guidelines recommend all of them be treated. It's important to note that we found low rates of antiviral use in all age groups."

The study also found wide geographic variation in the use of influenza antivirals -- there was a threefold to twentyfold difference in the rate of antiviral use based on geographic region that was not explained by differences in the incidence of flu, said Antoon.

"These findings highlight opportunities for improvement in the prevention and treatment of influenza, especially in the most vulnerable children," he added.

Potential reasons for underprescribing in children include a wide range of perceptions about efficacy, differences in interpretation of testing, a misunderstanding of the national guidelines and concern for adverse drug events associated with oseltamivir in children.

A previous 2023 study, led by Antoon, explored how often children diagnosed with influenza experience serious neuropsychiatric side effects.

In that study, Antoon and his team were able to quantify the number of pediatric neuropsychiatric events, describe which children are more likely to experience the events and showed that these relatively infrequent events occur in both those children treated and not treated with an antiviral.

"Treatment of children in the outpatient setting has been reported to decrease symptom duration, household transmission, antibiotic use and influenza- associated complications like ear infections," said Antoon.

The low rate of antiviral use in young children captured in the study along with recent evidence of low guideline-concordant antiviral treatment in children at high risk for influenza complications highlight the need for improved flu management in the most vulnerable children in the U.S., according to the study.

The study was funded by grants K23AI168496 from the National Institute of Allergy and Infectious Diseases (NIAID), which is part of the National Institutes of Health, an American Pediatrics Association Young Investigator Award and the Vanderbilt University Medical Center Turner Hazinski Research Award. Carlos Grijalva, MD, MPH, professor of Health Policy and Biomedical Informatics at Vanderbilt University Medical Center (K24AI148459) and Derek Williams, MD, MPH, chief of the Division of Hospital Medicine at Monroe Carell (RO1AI125642) both supported by the NIAID.