Viral replication kinetics of SARS-CoV-2 variants in ex vivo cultures of human respiratory tract. Viral replication of SARS-CoV-2 variants in human ex vivo nasal turbinate at 33°C (A and B), bronchus at 33°C (C, E, G) or 37°C (D, F, G) and lung at 37°C (H and I). The horizontal dotted line denotes the limit of detection in the TCID50 assay. Viral titres from A, C, D and H are depicted as area under the curve (AUC) (B, E, F, G and I). Data are presented as geometric mean values. Error bars indicate SD with N = 4 (nasal, individual donors); N = 5 (bronchus, individual donors); N = 6 (lung, individual donors). *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001, (A, C, D and H, Two-way ANOVA followed by Tukey's test; B, E, F and I, One-way ANOVA followed by Tukey's test; G, two-tailed T test).