The durability of immune memory after SARS-CoV-2 mRNA vaccination remains unclear. Here, we longitudinally profiled vaccine responses in SARS-CoV-2 naïve and recovered individuals for 6 months after vaccination. Antibodies declined from peak levels but remained detectable in most subjects at 6 months. We found mRNA vaccines generated functional memory B cells that increased from 3-6 months post-vaccination, with the majority of these cells cross-binding the Alpha, Beta, and Delta variants. mRNA vaccination further induced antigen-specific CD4+ and CD8+ T cells, and early CD4+ T cell responses correlated with long-term humoral immunity. Recall responses to vaccination in individuals with pre-existing immunity primarily increased antibody levels without substantially altering antibody decay rates. Together, these findings demonstrate robust cellular immune memory to SARS-CoV-2 and variants for at least 6 months after mRNA vaccination.

中文翻译：

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mRNA 疫苗诱导对 SARS-CoV-2 和相关变体的持久免疫记忆

SARS-CoV-2 mRNA 疫苗接种后免疫记忆的持久性仍不清楚。在这里，我们纵向分析了 SARS-CoV-2 未接种者和康复者在接种疫苗后 6 个月内的疫苗反应。抗体在 6 个月时从峰值水平下降，但在大多数受试者中仍可检测到。我们发现 mRNA 疫苗产生的功能性记忆 B 细胞在疫苗接种后 3-6 个月内有所增加，其中大多数细胞交叉结合 Alpha、Beta 和 Delta 变体。mRNA疫苗接种进一步诱导抗原特异性CD4+和CD8+T细胞，并且早期CD4+T细胞反应与长期体液免疫相关。回想一下，具有预先存在免疫力的个体对疫苗接种的反应主要是增加抗体水平，而不会显着改变抗体衰减率。总之，这些发现证明了在 mRNA 疫苗接种后至少 6 个月内对 SARS-CoV-2 及其变体具有强大的细胞免疫记忆。