IFNB1 and COVID-19: We found that patients who were on IFNβ treatment had lower IL-19 plasma level compared to those on corticosteroids or tocilizumab (Fig. 6, mean 24 ± 12.4 pg mL−1 in IFNβ-treated vs mean 39.2 ± 18.1 pg mL−1 in tocilizumab-treated, P = 0.016; and mean 42.5 ± 23.6 pg mL−1 in corticosteroid-treated COVID-19 patients, P = 0.031).