Relationship Between Frailty and Respiratory Syncytial Virus Infection in Hospitalized Older Adults

This study aimed to evaluate the impact of frailty on clinical outcomes and disease severity of respiratory syncytial virus (RSV) infection in older adults using data from the CIRN SOS Network (Serious Outcomes Surveillance Network; Canadian Immunization Research Network).

This cohort study used data from the CIRN SOS Network collected during the 2012-2013, 2013-2014, and 2014-2015 influenza seasons. Patients aged ≥50 years who were hospitalized for acute respiratory illness were tested for RSV by multiplex reverse transcription-polymerase chain reaction. The analysis focused on frailty to assess its association with RSV disease severity and clinical outcomes. Frailty was categorized as nonfrail, prefrail, and frail according to validated cutoffs based on baseline frailty index.

Among 365 older adults hospitalized for RSV-related acute respiratory infections, most were classified as frail (61.1%), with fewer classified as prefrail (28.5%) or nonfrail (10.4%). Frailty was significantly associated with severe RSV outcomes, such as prolonged hospitalization and increased oxygen therapy requirements. Specifically, frail patients experienced longer hospitalizations and higher intensive care unit admission rates, with an odds ratio of 3.48 (95% CI, 1.30-9.12) for the association between frailty and severe disease. While RSV types A and B showed no significant differences in clinical outcomes, chronic obstructive pulmonary disease and chronic kidney disease emerged as factors associated with disease severity, alongside frailty.

Frailty is an important predictor of RSV severity in older adults and is associated with longer hospital stays and increased health care needs. This highlights the need to consider frailty in RSV vaccine and therapeutic trials and suggests the potential benefits of interventions and public health and programmatic messaging tailored to older adults living with frailty.