IL6 and COVID-19: Sensitivity analysis without adjusting IL-6 levels for age and BMI levels at the time of plasma collection, produced almost identical results to the main analysis: β = 0.321 ± 0.115, p = 0.005; and β = − 0.061 ± 0.180, p = 0.774 for COVID-19-negative and COVID-19-positive participants, respectively.