Moreover, infection of B.1.1.7 and B.1.351 resulted in significant elevation of several key inflammatory cytokines in K18-hACE2 mice, including TNF-α (lung), IL-1β (lung), IL-6 (lung and liver), IL-13 (liver), IFN-α (liver) and IFN-β (liver). Here, IL1B is linked to infection.