Antibiotics
Aiya Almogaber, PharmD
Despite clear guidelines that discourage antibiotics for viral infections, a recent study reveals that RSV and influenza continue to drive a significant portion of pediatric antibiotic use in the United States.
Researchers estimate that RSV and flu account for 6.3% and 3.4% of outpatient antibiotic prescriptions among children, respectively. This amounts to more than 110 antibiotic prescriptions per 1,000 children annually.
Published online in The Journal of Infectious Diseases on June 7, 2025, the study underscores how diagnostic uncertainty and clinical habits continue to fuel unnecessary antibiotic use, even when viruses are the root cause. These findings highlight the growing need for integrated prevention strategies, including vaccination and stewardship, to lessen misuse and mitigate antibiotic resistance.
Tracking viral influence on prescriptions
To quantify the impact of RSV and influenza on antibiotic use, researchers used a retrospective time-series model drawing from Optum Clinformatics DataMart, which includes de-identified medical and pharmacy claims data. Weekly antibiotic prescriptions were regressed against viral activity data from both laboratory surveillance and clinical diagnoses.
Between 2008 and 2018, more than 21 million outpatient antibiotic prescriptions were dispensed to children aged 0 to 17 years, with over two–thirds linked to acute respiratory infection diagnoses. Researchers found that RSV and influenza were each independently associated with significant peaks in antibiotic use, particularly during seasonal surges in virus circulation.
On average, RSV led to 72.6 antibiotic prescriptions per 1,000 children per year, while influenza contributed 40 prescriptions per 1,000 children. These figures were even higher among children under 6 years old.
Age and diagnosis-specific breakdown
Children aged 0 to 5 years were particularly vulnerable, according to the study findings. The incidence of RSV-associated prescriptions reached 157.1 per 1,000 person-years in children aged 0 to 2 years and 124 per 1,000 among those aged 3 to 5 years. RSV was most frequently linked with conditions such as bronchiolitis, bronchitis, pneumonia, and acute otitis media (AOM)—conditions that often trigger antibiotics despite their viral etiology.
Influenza-associated prescribing was higher among older children. For children 6 years and older, influenza compared with RSV accounted for a greater share of prescriptions. Conditions most commonly linked to influenza prescribing included viral upper respiratory infections, bronchitis, and physician-coded RSV cases, reflecting diagnostic overlap and prescribing variability.
In the United States, AOM is one of the leading drivers of pediatric antibiotic use and is often treated inappropriately. The study found that RSV and influenza were associated with 10% and 4% of AOM-related antibiotic prescriptions, respectively. Additionally, both viruses were linked to approximately 13 and 11 prescriptions per 1,000 person-years for acute respiratory infection conditions where antibiotics were not guideline-recommended, such as bronchitis and viral upper respiratory infections.
Inappropriate use
The authors suggest that viral infections may trigger antibiotic use in three main ways: misdiagnosis of a viral infection as bacterial, treatment of possible secondary bacterial infections, or precautionary prescribing in uncertain cases. The study also noted the influence of coding practices that may incentivize diagnoses that justify antibiotic use.
In many outpatient settings, diagnostic testing for these viruses is limited, and treatment decisions are often made based on clinical suspicion alone.
These findings add urgency to the call for stronger outpatient stewardship programs. Macrolides and penicillins were the antibiotic classes most affected, according to study findings. RSV was associated with over 6% of macrolide and extended-spectrum b-lactam use, while influenza was associated with 4.4% of macrolide and 3.8% of penicillin prescriptions. ■