Early Antiviral Therapy in Pediatric Outpatients and Risk of Influenza-Related Hospitalization.

OBJECTIVES

Evidence on the effectiveness of antiviral therapy in preventing influenza-related severe illness and hospitalization among children remains limited. We hypothesized that early administration of antiviral therapy within 48 hours of symptom onset would significantly reduce the risk of subsequent influenza-related severe illness and hospitalization.

METHODS

This multicenter, age- and season-matched, retrospective case-control study included all pediatric outpatients with laboratory-confirmed influenza who sought care at the participating hospitals between 2020 and 2023. Cases were defined as children subsequently hospitalized or deceased because of influenza and were matched to nonhospitalized controls by date of initial visit and age strata. The effectiveness of early antiviral therapy (initiated within 48 hours of symptom onset, compared with delayed or no use) was estimated using conditional logistic regression. Subgroup analyses were performed for children aged 5 years or younger and older than 5 years.

RESULTS

Among 1492 children (354 cases and 1138 controls; mean age, 7.1 years), early antiviral therapy was associated with an 81% lower risk of hospitalization overall (adjusted odds ratio [aOR], 0.19; 95% CI, 0.14-0.27), with similar protection among children aged 5 years or younger (aOR, 0.19; 95% CI, 0.12-0.31) and older than 5 years (aOR, 0.15; 95% CI, 0.09-0.25). The effect remained robust across sensitivity analyses by antiviral agent, with E-values up to 10.0 (range, 9.47-19.49 across subgroups).

CONCLUSIONS

Early antiviral therapy in pediatric outpatients with influenza substantially reduces the risk of subsequent severe illness and hospitalization, supporting prompt initiation of treatment in this population.