Fig. 1: Evolution and neutralization characteristics of Omicron variant.

a, A linear representation of Omicron S with mutations indicated. The replacements are in red, deletions are in grey and insertions are in purple. b, Distribution of Omicron S mutations on the cryo-EM structure³⁴ of pre-fusion S trimer determined at pH 7.5 (Protein Data Bank (PDB) ID 7WG6). The mutations listed in a are indicated in the ‘up’ protomer shown in cartoon, with mutated residues highlighted as spheres and coloured as in a. The RBD, NTD, SD1 and S2 domains of this subunit are marked with arrows and coloured green, blue, magenta and yellow, respectively; the other two protomers are in the ‘down’ state and shown in surface representation in pale cyan and pale yellow. Alpha, B.1.1.7; Gamma, P.1; Lambda, C.37. c, The neutralizing antibody response against WT and Omicron SARS-CoV-2 authentic virus for sera from healthy vaccinees who received two (n = 60 volunteers) or three (n = 60 volunteers) doses of Coronavac. Data are geometric mean ± s.d. of technical triplicates. The dotted line represents the detection limit. NT₅₀ values of less than 4 were plotted as 2. Fold difference in neutralizing antibody titre Delta or Omicron over WT for each group of sera is shown above each set of points.