IL6 and congenital rubella syndrome: Although, the above-mentioned inflammatory markers had been described as prognostic factors, in a meta-analysis from Leisman et al. [26] serum levels of CRP, IL-6 and ferritin were compared between severe COVID-19 and other inflammatory diseases such as Cytokine Release Syndrome (CRS) and ARDS, revealing markedly decreased secretion of these markers compared to CRS and sepsis.