Exploring the Link Between RSV Infection and Antibiotic Prescriptions in Older Adults: A Systematic Review

Background/Objective: Respiratory syncytial virus (RSV) is an often under-recognized cause of respiratory illness in older adults. Clinical overlap with bacterial infections and delayed virologic confirmation may lead to the unnecessary prescription of antibiotics and antimicrobial resistance (AMR). This systematic review was conducted to assess antibiotic prescription in older adults with RSV and the factors influencing these decisions. Methods: This systematic review was preregistered in PROSPERO (CRD42024586905) and reported according to PRISMA guidelines. PubMed/MEDLINE, Embase, Web of Science, Cochrane CENTRAL, and Scopus were searched for studies published between January 2000 and August 2025. Eligible studies were those including adults aged ≥60 or ≥65 years with RSV infection and reporting antibiotic use. Data on antibiotic prescription, confirmed bacterial infection, hospitalization, length of stay (LOS), and prescribing indications were extracted. Results: Eight observational studies across inpatient, outpatient, emergency, and primary-care settings were included. Antibiotic prescribing ranged from 40.0% to 97.7%, whereas confirmed bacterial infection did not exceed 20% in any study. Antibiotic prescribing was associated with diagnostic uncertainty, radiologic findings, inflammatory markers, respiratory distress, delayed RSV testing, and multimorbidity rather than microbiological confirmation. Hospitalization rates varied across settings, and the LOS ranged from 3.5 to 11 days. None of the studies reported antibiotic discontinuation following RSV confirmation. Conclusions: Older adults with RSV frequently receive antibiotics despite low rates of confirmed bacterial infection, indicating substantial empirical prescribing. Improved rapid diagnostics, reassessment of therapy, and strengthened antimicrobial stewardship may help reduce unnecessary antibiotic use. RSV vaccination may be a promising strategy for reducing severe disease and hospitalization, with a potential indirect effect on antibiotic use, although these effects remain hypothetical.