Fig. 2. Experimental schedule and weight loss after challenge.
a Experiment schedule. Golden Syrian hamsters (8/group, equal sex) were immunized ID or IN twice (Week 0 and 3) with rLVS ΔcapB/SCoV2 vaccines, singly and in combination (MN + SΔTM; MN + S1); challenged IN 5 weeks later (Week 8) with 105 pfu of SARS-CoV-2 (2019-nCoV/USA-WA1/2020 strain), and monitored closely for clinical signs of infection including weight loss. Single vaccines expressed the S, SΔTM, S1, S2, S2E, or MN proteins, as indicated. Control animals were sham-immunized (PBS) or immunized with the vector (LVS ΔcapB) only. All hamsters were assayed for oropharyngeal viral load at 1, 2, and 3 days post challenge (dpi). Half of the hamsters (n = 4/group) were euthanized at 3 days post challenge for lung viral load analysis and half (n = 4/group) were monitored for weight loss for 7 days and euthanized at 7 days post challenge for lung histopathology evaluation. b Weight loss after challenge. Data are mean % weight loss from 0 days post challenge. *P < 0.05; **P ≤ 0.01; ***P < 0.001; ****P ≤ 0.0001 comparing means on Day 7 post challenge by repeated measure (mixed) analysis of variance model. Sham vs. MN: P < 0.0001, ID route; P < 0.01, IN route. The standard errors were omitted in the graphs for clarity.