2 peptide molecules can determine the severity of symptoms, complications, and the risk of death from COVID-19, said scientists at the Mount Sinai Hospital in New York. 

The results of their research were published in the journal Nature Medicine.

Scientists investigated 4 peptide molecules known as cytokines, which circulate in the blood and are usually associated with the immune response to infections. They found that 2 of these molecules - IL-6 and TNF-α - can determine the severity of symptoms, complication, and risk of death.

Scientists observed an increased level of these cytokines in the blood serum of critically ill patients. Moreover, this did not depend on other comorbidities in patients and demographic indicators such as age and gender.

The results of the studies showed that the risk of death in patients with elevated levels of IL-6 or TNF-α was 2 times higher, even taking into account other known risk factors. However, drugs such as the antiviral remdesivir or the corticosteroid dexamethasone can lower cytokine levels and contribute to a better outcome.