tetano
Editor, Senior Moderator
Open Forum Infect Dis
. 2025 Dec 18;13(1)
faf778.
doi: 10.1093/ofid/ofaf778. eCollection 2026 Jan. Outcomes Related to Bacterial Co-Infection and Antibiotic Use in Adults Hospitalized With Respiratory Syncytial Virus Compared with Influenza
Kristine L Karlsen[SUP] 1 [/SUP], Clara L Clausen[SUP] 1 [/SUP], Ragda A S Kahiyah[SUP] 2 [/SUP], Aymen Alkarawi[SUP] 2 [/SUP], Amanda M Egeskov-Cavling[SUP] 2 [/SUP], Noor Hayder[SUP] 2 [/SUP], Adin Sejdic[SUP] 2 [/SUP], Casper Roed[SUP] 2 3 [/SUP], Jon G Holler[SUP] 2 [/SUP], Lene Nielsen[SUP] 4 [/SUP], Mads F Eiberg[SUP] 2 [/SUP], Omid Rezahosseini[SUP] 2 [/SUP], Christian Østergaard[SUP] 5 [/SUP], Zitta B Harboe[SUP] 2 3 6 [/SUP], Thea K Fischer[SUP] 7 8 [/SUP], Birgitte Lindegaard[SUP] 2 3 [/SUP], Thomas Benfield[SUP] 1 [/SUP]
Affiliations
Background: Adults hospitalized with respiratory syncytial virus (RSV) face mortality risks comparable to or higher than those with influenza A or B. However, studies on the impact of bacterial co-infections on mortality are inconsistent.
Methods: This multicenter cohort study included adults hospitalized with RSV, influenza A, or B over 3 years at two tertiary care hospitals. Microbiological testing, bacterial co-infections, antibiotic use, and their association with clinical outcomes were analyzed using adjusted linear and logistic regression models.
Results: Of 986 patients, 352 (36%) had RSV, 347 (35%) influenza A, and 287 (29%) influenza B. The median age was 74 years, 54% were women, and 76% had at least one comorbidity. Overall, 32% had pneumonia. The prevalence of bacterial co-infections was comparable across patients with RSV (23%), influenza A (25%), and B (28%). Among patients without bacterial co-infection, antibiotic use within 48 hours remained common across all virus groups (77%, 71%, and 75%, respectively). In adjusted analyses, bacterial co-infection in patients with RSV was not associated with mortality at 14, 30, or 90 days, high-flow oxygen therapy, mechanical ventilation, or length of stay (LOS). Early antibiotic treatment was associated with prolonged LOS but not improved survival.
Conclusions: Bacterial co-infections were identified in approximately one-quarter of patients with RSV, influenza A, and B. Among patients with RSV, bacterial co-infection was not associated with adverse clinical outcomes, and early antibiotic treatment did not appear to improve clinical outcomes.
Keywords: antibiotic treatment; bacterial co-infections; clinical outcomes; influenza; respiratory syncytial virus.
. 2025 Dec 18;13(1)
faf778.doi: 10.1093/ofid/ofaf778. eCollection 2026 Jan. Outcomes Related to Bacterial Co-Infection and Antibiotic Use in Adults Hospitalized With Respiratory Syncytial Virus Compared with Influenza
Kristine L Karlsen[SUP] 1 [/SUP], Clara L Clausen[SUP] 1 [/SUP], Ragda A S Kahiyah[SUP] 2 [/SUP], Aymen Alkarawi[SUP] 2 [/SUP], Amanda M Egeskov-Cavling[SUP] 2 [/SUP], Noor Hayder[SUP] 2 [/SUP], Adin Sejdic[SUP] 2 [/SUP], Casper Roed[SUP] 2 3 [/SUP], Jon G Holler[SUP] 2 [/SUP], Lene Nielsen[SUP] 4 [/SUP], Mads F Eiberg[SUP] 2 [/SUP], Omid Rezahosseini[SUP] 2 [/SUP], Christian Østergaard[SUP] 5 [/SUP], Zitta B Harboe[SUP] 2 3 6 [/SUP], Thea K Fischer[SUP] 7 8 [/SUP], Birgitte Lindegaard[SUP] 2 3 [/SUP], Thomas Benfield[SUP] 1 [/SUP]
Affiliations
- PMID: 41488696
- PMCID: PMC12757863
- DOI: 10.1093/ofid/ofaf778
Background: Adults hospitalized with respiratory syncytial virus (RSV) face mortality risks comparable to or higher than those with influenza A or B. However, studies on the impact of bacterial co-infections on mortality are inconsistent.
Methods: This multicenter cohort study included adults hospitalized with RSV, influenza A, or B over 3 years at two tertiary care hospitals. Microbiological testing, bacterial co-infections, antibiotic use, and their association with clinical outcomes were analyzed using adjusted linear and logistic regression models.
Results: Of 986 patients, 352 (36%) had RSV, 347 (35%) influenza A, and 287 (29%) influenza B. The median age was 74 years, 54% were women, and 76% had at least one comorbidity. Overall, 32% had pneumonia. The prevalence of bacterial co-infections was comparable across patients with RSV (23%), influenza A (25%), and B (28%). Among patients without bacterial co-infection, antibiotic use within 48 hours remained common across all virus groups (77%, 71%, and 75%, respectively). In adjusted analyses, bacterial co-infection in patients with RSV was not associated with mortality at 14, 30, or 90 days, high-flow oxygen therapy, mechanical ventilation, or length of stay (LOS). Early antibiotic treatment was associated with prolonged LOS but not improved survival.
Conclusions: Bacterial co-infections were identified in approximately one-quarter of patients with RSV, influenza A, and B. Among patients with RSV, bacterial co-infection was not associated with adverse clinical outcomes, and early antibiotic treatment did not appear to improve clinical outcomes.
Keywords: antibiotic treatment; bacterial co-infections; clinical outcomes; influenza; respiratory syncytial virus.