Observational cohort links baloxavir to faster influenza A fever resolution in children

In a prospective observational cohort study of 750 children aged 5 to 14 with laboratory-confirmed influenza A, a single dose of baloxavir marboxil was associated with faster fever resolution than a five-day course of oseltamivir. The multicenter study enrolled children at eight community health centers in Chongqing, China, between October 2024 and December 2025. Median fever duration was 22.0 hours in the baloxavir group, compared with 40.5 hours in the oseltamivir group, with the difference reported as P < 0.001.

The researchers designed the study as a real-world, non-randomized comparison. Influenza A was confirmed by reverse transcription-polymerase chain reaction, and treatment was selected according to guardian preference rather than random assignment. The analysis was open-label, and fever duration was the primary outcome. Viral clearance, clinical complications, healthcare use, parental work absence, laboratory measures and adverse drug reactions were examined as exploratory outcomes, with false-discovery-rate adjustment used for the multiple exploratory comparisons. The investigators characterized the findings as hypothesis-generating because the preference-based design could not establish that the antiviral treatment caused the observed differences.

Baloxavir was associated with a shorter median time to viral clearance: 24.0 hours versus 72.0 hours with oseltamivir, with an FDR-adjusted P value below 0.001. The total complication rate was 3.7% among children given baloxavir and 11.2% among those given oseltamivir, corresponding to an FDR-adjusted P value of 0.042. Laboratory results also favored baloxavir in the exploratory analysis, showing more rapid normalization of inflammatory markers and the CD4-positive/CD8-positive ratio. The reported revisit rate was 2.1% with baloxavir compared with 6.9% with oseltamivir, and guardians reported fewer parental work-absence days: 2.0 days versus 3.5 days. The corresponding FDR-adjusted P values were 0.003 and below 0.001, respectively.

Safety outcomes showed a similar pattern. Adverse drug reactions were reported in 6.7% of the baloxavir group and 15.2% of the oseltamivir group, with an FDR-adjusted P value of 0.049. These findings describe associations observed in the enrolled cohort rather than causal effects demonstrated by a randomized comparison. Treatment allocation depended on guardian preference, the study was not blinded, and influenza A subtypes and substitutions associated with reduced viral susceptibility were not evaluated. The results therefore cannot establish that the differences arose solely from the antiviral regimens, nor can they be assumed to apply equally to all influenza A strains, seasons or patient populations.

Overall, the clearest result was the substantially shorter observed median fever duration after baloxavir than after oseltamivir. The additional findings for viral clearance, complications, revisits, parental work absence and adverse drug reactions were exploratory and support the possibility of broader benefits, but they do not provide definitive evidence that baloxavir is superior in every clinical outcome. By examining children treated in community health centers, the study adds real-world evidence to comparisons of pediatric influenza antivirals while also retaining the limitations inherent in an open-label, preference-based cohort. Children aged 5 to 14 with RT-PCR-confirmed influenza A were the population studied, and the results should be interpreted as associations within that setting rather than proof of a universal treatment advantage.

Subject of Research: Comparative effectiveness and safety of baloxavir marboxil and oseltamivir for influenza A in children aged 5 to 14 years

Article Title: Baloxavir marboxil versus oseltamivir for influenza A in children aged 5 years and older: a community-based prospective cohort study

Article References: Li, W., Zhou, M., Ye, H., Liu, L., & Yan, J. (2026). Baloxavir marboxil versus oseltamivir for influenza A in children aged 5 years and older: a community-based prospective cohort study. BMC Infectious Diseases, 26(1), Article 1707. https://doi.org/10.1186/s12879-026-14345-9

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14345-9

Keywords: influenza A, baloxavir marboxil, oseltamivir, pediatric influenza, antiviral treatment, fever duration, viral clearance, observational cohort, drug safety, Chongqing, Baloxavir, marboxil