While the mRNA delivery of hACE2 followed by infection with 5x104 FFU of SARS-CoV-2 did not allow our group to study viral pathogenesis in Ifnar1-/- mice, the delivery of hACE2 mRNA to our murine model allowed for the induction of a strong CD4+ and CD8+ T cell response to SARS-CoV-2 (Fig 3E). Here, CD4 is linked to infection.