Bortolotti et al. [106] showed in an in vitro system in which SARS-CoV-2 infection of Calu-3/MRC-5 multicellular spheroids induced the activation of the TLR3 pathway via IRF3, leading to pro-inflammatory cytokine secretion, including IL-1α, IL-1β, IL-4, IL-6, IFNα and IFNβ, during the first 24 h post-infection. Here, IL1A is linked to infection.