Given that iCoV2 + Alum induced type 2 inflammation during heterologous infection (Figs. 2f, g, 3), suggesting a strong TH2-biased immune response, we next tested the role of TH cells via CD4+ cell depletion in iCoV2 + Alum-vaccinated animals prior to SHC014 challenge (Supplementary Fig. 10b). Here, CD4 is linked to infection.