CD4 and influenza: At a low dose (0.01 μg), a sa‐mRNA encoding HA and NA antigens from H5N1, H3N2, H1N1 and Yamagata influenza strains elicited robust neutralising antibodies and CD4+ and CD8+ T‐cell responses in mice and protected ferrets from influenza at a 0.5 μg dose, with undetectable viral loads (Chang et al. 2022).