Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine rollout has coincided with the spread of variants of concern. We investigated whether single-dose vaccination, with or without prior infection, confers cross-protective immunity to variants. We analyzed T and B cell responses after first-dose vaccination with the Pfizer/BioNTech messenger RNA vaccine BNT162b2 in health care workers (HCW) followed longitudinally, with or without prior Wuhan-Hu-1 SARS-CoV-2 infection. After one dose, individuals with prior infection showed enhanced T cell immunity, antibody-secreting memory B cell response to the spike protein, and neutralizing antibodies effective against variants B.1.1.7 and B.1.351. By comparison, HCW receiving one vaccine dose without prior infection showed reduced immunity against variants. B.1.1.7 and B.1.351 spike mutations resulted in increased, abrogated, or unchanged T cell responses, depending on human leukocyte antigen (HLA) polymorphisms. Single-dose vaccination with BNT162b2 in the context of prior infection with a heterologous variant substantially enhances neutralizing antibody responses against variants.

严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 疫苗的推出与令人担忧的变种的传播同时发生。我们研究了单剂量疫苗接种（无论是否先前感染）是否能赋予针对变体的交叉保护性免疫力。我们分析了医护人员 (HCW) 首次接种辉瑞/BioNTech 信使 RNA 疫苗 BNT162b2 后的 T 和 B 细胞反应，并进行了纵向跟踪，无论是否曾感染过武汉-Hu-1 SARS-CoV-2。接种一剂后，先前感染过的个体表现出增强的 T 细胞免疫力、分泌抗体的记忆 B 细胞对刺突蛋白的反应，以及有效对抗变体 B.1.1.7 和 B.1.351 的中和抗体。相比之下，在未感染过的情况下接受一剂疫苗的医护人员表现出对变异病毒的免疫力下降。 B.1.1.7 和 B.1.351 刺突突变导致 T 细胞反应增加、消除或不变，具体取决于人类白细胞抗原 (HLA) 多态性。在先前感染异源变异的情况下，单剂量接种 BNT162b2 可显着增强针对变异的中和抗体反应。