Knowledge gaps over treating severe respiratory infections

There is a growing need to understand the scale of community-acquired severe respiratory viral infections (RVIs) in patients admitted to the ICU with respiratory failure, and to improve RVI therapies and associated care management plans. Together with scientists in Canada and the US, KAIMRC’s Yaseen Arabi has reviewed existing knowledge about RVI clinical care management around the world, highlighting pressing issues that require immediate attention. 

“The global pandemic has demonstrated the threat posed by RVIs and how devastating such viral infections can be,” says Arabi. “However, the diagnosis of RVIs depends on specialised molecular techniques, which are relatively new and not widely available. This means that on a global scale, the success of treatments and management of critically ill patients with RVIs is under-researched and poorly understood.” 

Recent technological advances mean that RVIs are increasingly being identified in adult patients who are hospitalised with respiratory tract problems such as pneumonia. Studies suggest that between 17 and 53 percent of such patients have an RVI. Linking patient symptoms directly to the viral infection can be challenging, although there is considerable evidence that many RVIs directly cause severe illness, particularly in the elderly and in immunosuppressed patients. 

“RVIs commonly affect the upper and lower respiratory tracts, reducing oxygen in the blood stream and disturbing the function of other organs,” says Arabi. “But every RVI is different and affects individuals in different ways. It may be that treatments should change at varying stages of these illnesses. Unfortunately, effective antiviral therapeutics for severe RVIs are limited.”

The most widely used drug is oseltamivir, a neuraminidase inhibitor that blocks the reproduction of the influenza virus inside host cells. When oseltamivir is used early in patients with severe influenza, it reduces mortality rates.  However, there are no clinically proven antivirals for treatment of other RVIs, and while immunomodulatory therapies have been trialled to improve the body’s immune response, none are currently recommended for RVI care in ICUs. 

Supportive care therefore remains the main response to RVIs in the ICU – patients receive ventilation aid, for example. The review highlights uncertainty regarding  the comparative effectiveness of different modalities of respiratory support, such as high-flow nasal oxygen, non-invasive ventilation, and invasive mechanical ventilation. 

“Data regarding supportive care, clinical outcomes and therapies is severely lacking for RVIs,” notes Arabi. “Across the world, we urgently need more randomised controlled trials to assess this efficiently and effectively.”

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