CD4 and infection: A substantial proportion of the activated CD4+ T cells in MVA-ZIKV vaccinated ZIKV-challenged mice also co-expressed TNF-α (~48% of cytokine-producing CD4+ T cells, Fig. S6F), suggesting that rapid protective vaccination with MVA-ZIKV induced potent ZIKV-E-specific CD4+ and CD8+ T cell responses that were significantly boosted immediately after infection.