Impact of SARS-CoV-2 infection on immunologic response to BNT162b2 in patients with MM. (A-C) Patients with MM with a history of infection with SARS-CoV-2 (more than 3 months before vaccination) who developed their infection at any time after vaccination or who had never had SARS-CoV-2 infection. (A) S-Flow IgG quantification (history of SARS-CoV-2 infection, n = 11; post-vaccine SARS-CoV-2, n = 4; other, n = 56). (B) Alpha (left) or delta (right) nAb quantification (history of SARS-CoV-2 infection, n = 11; post-vaccine SARS-CoV-2, n = 4; other, n = 56). (C) S1 (left) or S2 (right) IFN-γ EliSpot (SARS-CoV-2 history, n = 5; other, n = 21). Error bars represent standard error. *P < .05; ***P < .001; ****P < .0001. ns, not significant.