Fig. 2. (A, B) Time course of anti-Spike immunoglobulin G (IgG) in coronavirus disease (COVID)-recovered vaccinees (individuals d, e, and f). Vaccinations were performed at day 1 and 28. Some participants could not provide samples at each time point (participant ‘e’: day 6–7, day 31–32, and day 37–40; participant ‘f’: day 34–35 and day 37–40). The lacking samples are depicted as Φ.
