Interfacial hydrogen bonds between proteins for WT, delta, BA1, and BA2. All bars represent 95% CI. (A–E) BA1 and BA2 variants participate in significantly fewer interactions than WT and Delta for the simulations shown, with the exception of Delta and BA2 in (E). All pairwise P-values in Fig. 2A through E are P < 0.0001 (highly significant), with the exception of the aforementioned Delta versus BA2 pair in (E) (P = 0.19, not significant), the BA1 versus BA2 pair in (B) (P = 0.82, not significant), the WT versus delta pair in (C) (P =0.09, not significant), and the BA1 versus BA2 pair in (D) (P = 0.01, significant). (F) FCD-Furin H-bond interactions. All omicron variants participate in slightly higher interactions than WT but less than Delta. We also consider the possibility of the FCD for the omicron variants starting at 679K in Omicron (Alt). All pairwise P-values in (F) are P < 0.001 (highly significant). All PDB files are referenced in the methods section and provided in the repository referenced in the supplemental material.