Viral load is strongly associated with length of stay in adults hospitalised with viral acute respiratory illness

- It is not known if viral load is associated with length of stay in viral acute respiratory illness.
- We examined 306 adult patients hospitalised with confirmed viral acute respiratory illness.
- High viral load was associated with longer length of stay for all virus subtypes and all clinical groups.
- This could be used in clinical practise to identify high risk patients and prioritise antivirals.

SummaryBackgroundRespiratory viruses are detectable in a large proportion of adults hospitalised with acute respiratory illness. For influenza and other viruses there is evidence that viral load and persistence are associated with certain clinical outcomes but it is not known if there is an association between viral load and hospital length of stay.Methods306 adults hospitalised with viral acute respiratory illness were studied. Associations between viral load and length of stay were examined. Multiple linear regression analysis was performed to control for age, comorbidity, influenza vaccine status, duration of illness prior to hospitalisation, bacterial co-infection, clinical group and virus subtype.ResultsHigh viral load was associated with a longer duration of hospitalisation for all patients (p < 0.0001). This remained significant across all virus types and clinical groups and when adjusted for age, comorbidity, duration of illness prior to hospitalisation, bacterial co-infection and other factors.ConclusionsHigh viral loads are associated with prolonged hospital length of stay in adults with viral acute respiratory illness. This further supports existing evidence demonstrating that viral acute respiratory illness is a viral load driven process and suggests that viral load could be used in clinical practise to predict prolonged hospitalisation and prioritise antivirals.International Standard Randomised Controlled Trial Number (ISRCTN): 21521552