Health Outcomes

NIRV vs Influenza: Which Is Deadlier?

The rate of illness and death in patients with noninfluenza respiratory viral infections (NIRV) may be similar to those of influenza in hospitalized adults, according to the results of a recent study.

The researchers conducted an analysis of 2 hospital-based surveillance cohorts to examine the burden, severity, and outcomes of NIRV infections in comparison to influenza. Included were patients who were hospitalized for influenza-like illness or pneumonia within 2 regions of Canada over 3 consecutive seasons from 2015 to 2018.

Of the 2119 total patients admitted to the hospital, 54.6% (n = 1156) had NIRV infections while 45.4% (n = 963) had influenza. Both groups were similar in admission to ICU, hospital length-of-stay, and 30-day mortality. Overall, 21.1% of patients with NIRV infections required respiratory support, 18.2% required ICU care, and 8.4% of NIRV patients died within 30-days of diagnosis.

The results also revealed that 14.6% of NIRV infections were hospital-acquired. NIRV patients were often younger, had immunocompromising conditions, and had a delay in their diagnosis. The most common NIRV infections included respiratory syncytial virus, human rhinovirus, and human coronavirus.

NIRV infections account for a substantial proportion of the disease burden among adults admitted to hospital with respiratory tract infections,” the researchers concluded. “They are associated with severe clinical outcomes, similar to influenza. Our findings highlight unmet needs and research gaps in therapeutics and vaccines for people at high risk of NIRV infection.”


—Leigh Precopio



Lee N, Smith S, Zelyas N, et al. Burden of noninfluenza respiratory viral infections in adults admitted to hospital: analysis of multiyear Canadian surveillance cohort from 2 centres. CMAJ. 2021; 193(13): E439-E446. doi: /10.1503/cmaj.201748