Clinical isolates of XBB.1, XBB.1.5, and Delta were inoculated into an airway-on-a-chip system. The copy numbers of viral RNA in the top (left) and bottom (middle) channels of an airway-on-a-chip were routinely quantified by RT-qPCR. On the right, the percentage of viral RNA load in the bottom channel per top channel at 6 d.p.i. (i.e., % invaded virus from the top channel to the bottom channel) is shown. Assays were performed in triplicate (A, G) or quadruplicate (B-F). The presented data are expressed as the average SD (A, B) or SEM (C-G). Statistically significant differences versus XBB.1 across timepoints were determined by multiple regression (B-E and G left) or a two-sided Student’s t test (G right). The FWERs calculated using the Holm method are indicated in the figures. NA, not applicable.
