The early infection plasma samples at B2 showed the highest IgM and IgA reactivity to receptor binding domain (RBD) and subunit S1 (S1) (IgA RBD median [1Q, 3Q] in B2 = 1.72 [1.19, 2.01] [n = 85] versus 1.10 [0.85, 1.33], 1.00 [0.62, 1.29], and 0.60 [0.43, 1.34] in C3 [n = 209], A1 [n = 56], and A2 [n = 52], respectively; Fig. 2B and C; Fig. S2). The gene discussed is CD40LG; the disease is infection.