Potency against WT was considerably improved after Delta breakthrough infection compared to the second vaccine dose (Vax2; IC50 = 182 ng/ml vs. IC50 = 50 ng/ml, P = 0.0013; Fig. 3 b) but not compared to the third vaccine dose (IC50 = 98 ng/ml, P = 0.62; Fig. 3 b). The gene discussed is VAX2; the disease is infection.