The augmented antigenic load has been suggested to affect qualitative aspects of CD8+ T-cell memory/effector responses [67,68] and, despite our results indicate that sheep immunized with ChAdOx1/MVA-NS1 were protected against BTV-4M infection, it would be interesting to analyze whether higher doses of vaccine are still safe for ruminants and completely reduce viremia after BTV infection. Here, CD8A is linked to infection.