Flu antiviral use is falling--in children guidelines target

Clinical takeaway: Late presentation is not a reason to withhold oseltamivir from a hospitalized child with influenza. Lower ICU risk held for treatment started three or more days after symptom onset.

CDC, the American Academy of Pediatrics, and the Infectious Diseases Society of America all agree on one instruction for a child admitted with suspected or confirmed influenza: start oseltamivir as soon as possible, whatever the symptom duration. No window, no risk-factor screen, no waiting on confirmation.

But in practice, treatment has become a decision at each bedside, weighed against how many days of fever came first and how much anyone still believes the drug does for a child already sick enough for admission. Only 63% of hospitalized US children got an antiviral in the 2024-2025 season, down from 86% in 2017-2018, and receipt has ranged from 26% to 74% across surveillance sites.

Children at higher risk for complications are seeing declines as well. Survey work keeps surfacing the same three drivers: symptom duration, doubt about effectiveness, and lingering concern about neuropsychiatric events traced to a 2005 safety update that later studies have not borne out. A new study attempts to put the effectiveness question to rest.

Late treatment held up. Starting oseltamivir three or more days after symptom onset was tied to a 45% lower hazard of ICU admission, no worse than the 26% reduction seen with treatment inside two days. Lower risk persisted past five days of illness, on fewer children and a wide margin of error.

Any treatment, at any point, tracked with 31% lower ICU risk, measured from symptom onset rather than from admission. Excluding children treated before arrival did not change it. Hospital stay fell by about nine hours with treatment, to 3.33 days from 3.72 days, a gain that held only for children treated within two days.

Investigators drew on FluSurv-NET, a CDC network abstracting charts on laboratory-confirmed influenza hospitalizations in 13 states, and analyzed 6,044 children younger than 18 across eight seasons through 2022-2023. Median age was three years, half had a comorbidity, and 70% received oseltamivir. Unlike earlier pediatric studies built on billing codes, this one used confirmed infections, captured treatment started before arrival, and timed exposure from symptom onset rather than admission.

The operational shift is small and worth making: stop calculating symptom days when a child is being admitted with influenza and treat on admission status alone. The children in this cohort who were treated late were not a salvage population.

"After one of the most severe influenza seasons in the past two decades, these findings reinforce the importance of treating children with influenza who are hospitalized. Our findings show that oseltamivir treatment can decrease the risk of needing critical care, even if started beyond the first two days of the start of the illness," said Suchitra Rao, MBBS, MSCS, professor of pediatrics at the University of Colorado Anschutz School of Medicine, infectious disease specialist at Children's Hospital Colorado, and senior author of the study.

Source: Rytlewski K, et al. (2026 Aug 10) JAMA Pediatr. Effectiveness of Oseltamivir in Hospitalized Children With Laboratory-Confirmed Influenza, 2014-2023