NECTIN4 and lymphopenia: Only animals inoculated with recCDV NΔ425-479 experienced lymphocytopenia with initial kinetics similar to that of the recCDV-infected group (Fig. 2f; Supplementary Fig. S7a–d), whereas no statistically significant changes in lymphocyte counts were detected in ferrets infected with recCDV Nectin-4-blind, confirming over-attenuation of this recombinant.