Characterizing Oseltamivir Use Among Community-Dwelling Patients Diagnosed With Influenza Virus Infection, 2023-2025.

BACKGROUND

Oseltamivir is an antiviral medication for influenza that can reduce the duration of symptoms and may lower the risk of some complications. Recommendations for use of oseltamivir include in the outpatient setting for individuals at higher risk of developing influenza complications. The objectives of the current study were to describe oseltamivir initiation and treatment completion among influenza-positive outpatients and identify factors associated with each.

METHODS

In a US outpatient household transmission study, index participants with laboratory-confirmed influenza provided up to 12 days of detailed information on medication use. We described oseltamivir initiation among index case patients and treatment course completion of ≥10 doses among patients who started oseltamivir. We used adjusted logistic regression to identify factors associated with initiation and course completion.

RESULTS

Among 823 enrolled index patients, 324 (39%) initiated oseltamivir treatment. Of 406 persons at higher risk for influenza complications, 172 (42%) initiated treatment. Oseltamivir initiation was lowest among children aged 2-4 years (19%), compared with all other age groups. After exclusion of the likely censored cases, 133 of 313 patients (42%) completed the recommended treatment course. Among 163 individuals at higher risk of influenza complications, 69 (42%) completed the recommended treatment course. Children <2 years old were significantly less likely to complete treatment than adults aged 18-50 years (adjusted odds ratio, 0.21 [95% confidence interval, .04-.78; P = .03); the reasons for discontinuation could not be determined.

CONCLUSIONS

In this population in the outpatient setting, fewer than half of persons at higher risk for influenza complications initiated oseltamivir treatment, and fewer than half of those who initiated treated completed it.