Fig. 2. Morbidity, viral replication, pathology, and tissue distribution of viral RNA after MA-SARS-CoV-2 infection of 129S1 mice.

A Evolution of body weight relative to initial body weight after infection with 2.5 × 10⁴ PFU WT-SARS-CoV-2 (n = 5), PBS/mock (n = 3), and two doses of MA-SARS-CoV-2 (n = 20 for 2.5 × 10⁴ PFU, n = 5 for 2.5 × 10⁵ PFU). Differences were compared to PBS group. Each dot represents individual animal and the error bar represents mean ± SEM. Two-sided unpaired t-test was performed to determine the statistical difference in reference to the mock group at different DPI. B Viral load in whole lungs and nasal turbinates during the course of infection with 2.5 × 10⁴ PFU of MA-SARS-CoV-2 as measured by plaque assay (n = 4). PFU = plaque-forming units. C Cumulative pathology scored during the course of infection with 2.5 × 10⁴ PFU of MA-SARS-CoV-2 (n = 3 for mock; n = 4 for other groups). Each dot represents individual animal, and the bar represents geometric mean in respective group. Two-tailed Mann–Whitney U test was performed to determine the statistical difference between mock and 1DPI. D Genomic RNA copies in different tissues at different time points post-infection with 2.5 × 10⁴ PFU of MA-SARS-CoV-2 quantified by qRT-PCR using primers specific for the N gene (n = 3). Two-sided unpaired t-test was performed to calculate the statistical significance between different groups. Bars represent geometric means; error bars represent standard deviation. Dotted line indicates limit of detection (LOD) = 66.67 PFU/ml. Each data point corresponds to each mouse in the group and the number of data points represents the number of mice in the corresponding groups. Source data are provided as a Source Data file.