More than one year after its inception, the coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains difficult to control despite the availability of several working vaccines. Progress in controlling the pandemic is slowed by the emergence of variants that appear to be more transmissible and more resistant to antibodies^1,2. Here we report on a cohort of 63 individuals who have recovered from COVID-19 assessed at 1.3, 6.2 and 12 months after SARS-CoV-2 infection, 41% of whom also received mRNA vaccines^3,4. In the absence of vaccination, antibody reactivity to the receptor binding domain (RBD) of SARS-CoV-2, neutralizing activity and the number of RBD-specific memory B cells remain relatively stable between 6 and 12 months after infection. Vaccination increases all components of the humoral response and, as expected, results in serum neutralizing activities against variants of concern similar to or greater than the neutralizing activity against the original Wuhan Hu-1 strain achieved by vaccination of naive individuals^2,5,6,7,8. The mechanism underlying these broad-based responses involves ongoing antibody somatic mutation, memory B cell clonal turnover and development of monoclonal antibodies that are exceptionally resistant to SARS-CoV-2 RBD mutations, including those found in the variants of concern^4,9. In addition, B cell clones expressing broad and potent antibodies are selectively retained in the repertoire over time and expand markedly after vaccination. The data suggest that immunity in convalescent individuals will be very long lasting and that convalescent individuals who receive available mRNA vaccines will produce antibodies and memory B cells that should be protective against circulating SARS-CoV-2 variants.

由严重急性呼吸系统综合症冠状病毒 2 (SARS-CoV-2) 引起的 2019 年冠状病毒病 (COVID-19) 大流行发生一年多后，尽管已有多种有效疫苗，但仍难以控制。似乎更易传播且对抗体更具抵抗力的变体的出现减缓了控制大流行的进展^1,2。在这里，我们报告了一组 63 名从 COVID-19 中康复的人，他们在 SARS-CoV-2 感染后 1.3、6.2 和 12 个月进行了评估，其中 41% 的人还接种了 mRNA 疫苗^3,4. 在没有接种疫苗的情况下，抗体对 SARS-CoV-2 受体结合域 (RBD) 的反应性、中和活性和 RBD 特异性记忆 B 细胞的数量在感染后 6 至 12 个月内保持相对稳定。疫苗接种增加了体液反应的所有组成部分，并且正如预期的那样，导致针对相关变体的血清中和活性类似于或大于通过对幼稚个体进行疫苗接种实现的针对原始武汉 Hu-1 毒株的中和活性^{2,5,6， 7,8}。这些基础广泛的反应背后的机制涉及持续的抗体体细胞突变、记忆 B 细胞克隆周转和对 SARS-CoV-2 RBD 突变特别有抵抗力的单克隆抗体的开发，包括在关注的变体中发现的突变^4,9。此外，表达广泛和有效抗体的 B 细胞克隆会随着时间的推移选择性地保留在库中，并在接种疫苗后显着扩增。数据表明，恢复期个体的免疫力将持续很长时间，接受可用 mRNA 疫苗的恢复期个体将产生抗体和记忆 B 细胞，这些抗体和记忆 B 细胞应该可以防止循环的 SARS-CoV-2 变体。