Detectable viral load and IL-6: a role for tocilizumab or anti-JAK inhibitor baricitinib?

Simon Collins, HIV i-Base

A study of 48 participants (31 men, 17 women) enrolled in a COVID-19 hospital in Wuhan City, China, reported a close correlation between disease severity and both RNA viral load in serum and elevated levels of IL-6.

No cases were categorised as mild; 21 were moderate (43%), 10 severe cases (21%), and 17 critically ill cases (35%). Although viral load in throat samples was positive in all patients, serum PCR was only positive in five patients who were critically ill, two of whom died.

Peripheral blood leukocytes inversely correlated with severity of COVID-19 and IL-6 was sharply increased in critical patients, 10-fold higher than that in severe patients, all exceeding 100 pg/mL.

RNA and IL-6 were both closely correlated with severe illness (r=0.902) and patients with higher levels had great risk of organ damage.

The researchers concluded with a discussion on plausible benefit from using anti-inflammatory drugs such as tocilizumab or the anti-JAK inhibitor baricitinib, currently licensed and with safety data to treat rheumatoid arthritis, some of which have already reported encouraging results in open-label uncontrolled studies. [2, 3]


  1. Chen X et al. Detectable serum SARS-CoV-2 viral load (RNAaemia) is closely correlated with drastically elevated interleukin 6 (IL-6) level in critically ill COVID-19 patients. Clin Infect Dis. 2020 Apr 17: ciaa449. DOI: doi: 10.1093/cid/ciaa449. (17 April 2020).
  2. Xu X et al. Effective treatment of severe COVID-19 patients with tocilizumab. PNAS, DOI: 10.1073/pnas.2005615117. (29 April 2020).
  3. Cantini F et al. Baricitinib therapy in COVID-19: A pilot study on safety and clinical impact. J Infect. doi: 10.1016/j.jinf.2020.04.017. (23 April 2020).

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