Fig. 7. Efficacy of transmission block by CVXGA1 immunization in ferrets.
(A) Schematic of ferret immunization, viral challenge, and transmission. Groups of six ferrets were immunized (CVXGA1), with empty viral vector or mock-immunized (PBS) at a dose of 106 PFU intranasally. Ferrets were challenged at 42 dpi with 4 × 105 PFU of SARS-CoV-2 intranasally. Nasal washes were collected at 1, 3, 5, 7, 9, and 11 dpc. Half of the ferrets were humanely euthanized 4 days after challenge. The study ended at 11 dpc. At 2 dpc, one challenged ferret was mixed with one naïve ferret, and nasal washes were collected from naïve ferrets at 1, 3, 5, 7, and 9 days after mixing (3, 5, 7, 9, and 11 dpc, respectively). (B) Detection of SARS-CoV-2 at 1, 3, 5, 7, 9, and 11 dpc in nasal washes. Live virus was detected using FFA (FFU per milliliter) as described in Materials and Methods. Each symbol represents a different animal. The limit of detection is indicated by the lowest dashed line.