IFNL1 and COVID-19: Interestingly, in contrast to identified systemic cellular ISG responses, non-hospitalized mild cases had a significantly lower levels of interferon type II and type III (IFN-λ1, IFN-λ2/3 and IFN-γ) at early timepoints of infection (d4) compared to hospitalized COVID-19 patients (Fig. 7h).