Pediatricians using rapid antigen diagnostic tests (Ag-RDTs) for respiratory syncytial virus (RSV) in outpatients presenting with lower respiratory tract infection symptoms issued 48% fewer antibiotic prescriptions than those making clinical diagnoses without Ag-RDTs, in a study1 described by the investigators as the first to evaluate that interaction in pediatric primary care.
The difference in antibiotic prescribing between pediatricians who did or did not obtain testing for their pediatric outpatients was notable; as was the difference from previous studies in hospital and emergency department settings which have not associated RSV testing with less antibiotic prescribing.
The investigators suggest several factors for the disparate findings, including that this outpatient population ranged older in age and presented with less symptom severity than those studied in hospital and emergency departments.
"These (different) findings may reflect clinicians' heightened concern about severe outcomes or bacterial co-infections in younger, more susceptible children," suggests lead author Riccardo Boracchini, MSc, Laboratory of Healthcare Research and Pharmacoepidemiology, University of Milan-Bicocca, Milan, Italy, and colleagues.
What You Need to Know
Pediatricians who used rapid antigen diagnostic tests (Ag-RDTs) for RSV prescribed 48% fewer antibiotics compared to those relying on clinical judgment alone, highlighting the test’s value as an antimicrobial stewardship tool in outpatient care.
Unlike prior studies in hospital and emergency department settings, this outpatient study found a strong link between RSV testing and reduced antibiotic prescribing—likely due to differences in patient age, illness severity, and clinician risk perception.
Even with testing, factors like perceived illness severity and concern for bacterial co-infection continue to shape antibiotic use, and some uncertainty remains due to potential confounding that wasn’t fully accounted for in the study.
In an accompanying editorial,2 Carl Llor, PhD, Research Unit for General Practice, University of Southern Denmark, Odense-Aabenraa Denmark, agreed that "clinicians are more inclined to prescribe antibiotics to patients perceived as more severely ill." He points out, however, that disease severity was not systematically accounted for in the outpatient study.
"While the authors attempted to address this issue by excluding cases with clear indicators of severe illness or documented bacterial co-infection, residual confounding related to subtler differences in clinical presentation or clinician risk perception cannot be excluded," Llor observed.
Boracchini and colleagues accessed data from Pedianet, a network of over 200 family pediatricians in Northern and Central Italy, identifying a cohort of 26 pediatricians treating 256 cases of lower respiratory tract infections in children aged 9 to 36 months between December 2023 and May 2024. They further refined the data through access to the Evolute study, a prospective observational study assessing Ag-RDTs for RSV, influenza and COVID-19.
The investigators compared antibiotic prescribing for the following subgroups: RSV-positive vs RSV-negative; RSV-tested (either positive or negative) vs clinically diagnosed viral lower respiratory tract infection (VLRTI); RSV-positive vs clnically diagnosed VLRTI; RSV –tested vs clinically diagnosed bronchiolitis cases in children younger than 24 months; and RSV-positive vs clinically diagnosed bronchiolitis in children younger than 24 months.
Boracchini and colleagues reported lower antibiotic prescribing in RSV-positive than RSV-negative children (0.18 VS 0.29 prescriptions per 10 person-days), with reduced relative risk (RR) of receiving an antibiotic prescription of 0.52 (95%CI, 0.33-0.83).Implementation of RSV Ag-RDT was associated with lower antibiotic use for VLRTIs than in a matched, untested cohort (RR, 0.54 [0.44-0.66] in 2022-2023 and 0.61 [0.50-0.75] in 2023-2024; as well as for bronchiolitis in 2022-2023, but not in 2023-2024.
The investigators concluded that "RSV Ag-RDT was a useful outpatient antimicrobial stewardship tool, particularly in bronchiolitis.Combined with universal immunoprophylaxis, widespread Ag-RDT use may improve diagnostic accuracy, resource allocation, and clinical outcomes."
Llor concurred, characterizing this study as an "important step forward in advancing our understanding of the impact of rapid RSV testing on antibiotic prescribing in primary care."
This remains significant as RSV incidence rates remain high. According to the Centers for Disease Control and Prevention (CDC), 7.5% of tests were positive for the third week of March, which is 2.5% higher than the same time last year.3
References
1. Boracchini R, Brigadoi G, Salvadori S, et al. RSV detection and antibiotic prescribing decisions for pediatric respiratory tract infections. JAMA Netw Open. 2026; 9(3):e260409. doi:10.1001/jamanetworkopen.2026.0409.
2. Lior C. RSV detection and antibiotic prescribing. JAMA Netw Open. 2026; 9(3):e60416. doi:10.1001/jamanetworkopen.2026.0416.
