Background: National guidelines recommend antiviral treatment for children with influenza at high-risk for complications regardless of symptom duration. Little is known about concordance of clinical practice with this recommendation.

Methods: We performed a cross-sectional study of outpatient children (1-18 years) at high-risk for complications who were diagnosed with influenza during the 2016-2019 influenza seasons using the MarketScan Medicaid database. High-risk status was determined using an existing definition including age, co-morbidities, and residence in a long-term care facility. The primary outcome was influenza antiviral dispensing within 2 days of influenza diagnosis. We determined patient and provider level factors associated with guideline concordant treatment using multivariable logistic regression.

Results: Of the 274,213 children with influenza at high-risk for influenza complications, 11,4863 (58.1%) received antiviral treatment. Antiviral treatment was associated with the presence of asthma (adjusted odds ratio 1.13, 95% CI 1.11, 1.16), immunosuppression (aOR 1.10, 95% CI 1.05, 1.16), complex chronic conditions (aOR 1.04, 95% CI 1.01,1.07) and index encounter in the urgent care setting (aOR 1.3, 95% CI 1.26, 1.34). Factors associated with decreased odds of antiviral treatment include age 2-5 years compared to 6-17 years (aOR 0.95, 95% CI 0.93, 0.97), residing in a chronic care facility (aOR 0.61, 95% CI 0.46, 0.81), and index encounter in an emergency department (aOR 0.66, 95% CI 0.63, 71).

Conclusions: Among children with influenza at high-risk for complications, 42% did not receive guideline concordant antiviral treatment. Further study is needed to elucidate barriers to appropriate use of antivirals in this vulnerable population.