IL6 and COVID-19: Furthermore, a comparison of the levels of important inflammatory and clinical markers in COVID-19 patients between the first and second wave showed a significant reduction of C-reactive protein (CRP) (Fig 9G) and IL-6 levels (Fig 9H) as well as decreased length of ICU stay (Fig 9I) and ventilation days (Fig 9J) in patients suffering from a bacterial superinfection during the second wave.