Out-of-pocket costs and productivity losses associated with influenza illness and caregiving in a household study in the United States, 2024-2025

Background: Non-medically attended (NMA) and outpatient medically attended (MA) influenza illnesses contribute substantially to influenza disease burden in the United States. We leveraged a household study to estimate out-of-pocket and lost productivity costs of NMA and MA influenza illness. Methods: The Respiratory Virus Transmission Network for Influenza was a 2024-2025 case-ascertained household study at 3 U.S. sites. Influenza-positive index patients and household contacts self-reported daily symptoms, over-the-counter (OTC) medication use, medical care-seeking, time missed from work or activities, and self-collected nasal swabs for PCR testing. We included participants with PCR-confirmed influenza infection and influenza-like-illness symptoms who ever (MA) or never (NMA) sought medical care during follow-up. We obtained costs of OTC medications from retail websites and productivity costs from published values. We calculated OTC medication and lost productivity costs in 2025 USD for MA and NMA influenza separately and household-level lost productivity costs among caregivers for MA and NMA household members. Results: Median out-of-pocket OTC medication costs were $6.38 (interquartile range [IQR] $2.92-$11.60) among 594 MA and $3.72 (IQR $1.50-$7.05) among 153 NMA influenza illnesses. Among participants ≥15 years of age, median lost productivity was $315 ($149-$743) for MA and $248 ($0-$624) for NMA illnesses. Median household-level lost productivity for caregiving was $148 (households with 1 ill child), $379 (multiple ill children), and $0 (≥1 ill adult). Conclusions: Influenza causes substantial lost productivity costs within households. These estimates can inform future economic burden and cost effectiveness analyses.