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期刊来源：Nat Med

原文链接：https://doi.org/10.1038/s41591-024-02962-3

摘要内容如下：

缺乏关于疫苗诱导的免疫应答寿命的信息和保护相关性的不确定性阻碍了新出生队列的循证COVID-19疫苗接种政策的发展。在这里，为了填补这些知识空白，我们对接种了BNT162B2疫苗的5-12岁健康儿童进行了队列研究。我们在1年内连续测量了结合和中和抗体滴度（NAbs）、尖峰特异性记忆B细胞（MBC）和尖峰反应性T细胞应答。我们发现儿童在接种两剂BNT162B2后出现抗体、MBC和T细胞应答，在接种后6个月比成人具有更高的抗体和T细胞应答。加强（第三）剂量仅改善抗体滴度而不影响MBC和T细胞应答。在混合免疫的儿童中，两次接种疫苗后，NAbs和T细胞应答在感染者中最高。结合IgG效价、MBC和T细胞应答是可预测的，其中T细胞是杂交免疫前对症状性感染保护的最重要预测因子；NABS仅与杂交免疫后的保护作用相关。随着时间的推移，稳定的MBC和T细胞反应表明，即使在NABS减弱时，对有症状的SARS-CoV-2感染也有持续的保护作用。加强接种疫苗并不能为健康儿童提供额外的免疫保护。

英文原文如下：

Abstracts

The paucity of information on longevity of vaccine-induced immune responses and uncertainty of the correlates of protection hinder the development of evidence-based COVID-19 vaccination policies for new birth cohorts. Here, to address these knowledge gaps, we conducted a cohort study of healthy 5-12-year-olds vaccinated with BNT162b2. We serially measured binding and neutralizing antibody titers (nAbs), spike-specific memory B cell (MBC) and spike-reactive T cell responses over 1 year. We found that children mounted antibody, MBC and T cell responses after two doses of BNT162b2, with higher antibody and T cell responses than adults 6 months after vaccination. A booster (third) dose only improved antibody titers without impacting MBC and T cell responses. Among children with hybrid immunity, nAbs and T cell responses were highest in those infected after two vaccine doses. Binding IgG titers, MBC and T cell responses were predictive, with T cells being the most important predictor of protection against symptomatic infection before hybrid immunity; nAbs only correlated with protection after hybrid immunity. The stable MBC and T cell responses over time suggest sustained protection against symptomatic SARS-CoV-2 infection, even when nAbs wane. Booster vaccinations do not confer additional immunological protection to healthy children.

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