Consistent with our prior results, the prototype unadapted SHIV Q23AE exhibited a pronounced IFNα-induced inhibition of viral replication (6.7-fold at day 9 post infection) whereas the adapted SHIV AD8-EO was largely resistant to IFNα (AUC ratio 0.86 vs 0.96, p = 0. Here, IFNA1 is linked to infection.