变异株|新冠病毒Delta变异株强势反击,防疫需借鉴疫苗的现实世界数据( 二 )


研究结果表明:
辉瑞疫苗两针间隔时间无论短还是长,总体上都产生了强烈的免疫反应 。
3周疫苗间隔产生的中和抗体比与10 周间隔少 。
第一针以后,虽然抗体水平有所下降,但 T 细胞(细胞免疫)的水平仍然很高 。
更长的间隔时间虽然导致总T 细胞较少,但其中一个特定的类型,被称为辅助 T 细胞,比例更高 。而这种细胞是支持免疫记忆的关键 。
这项研究的首席研究员 Susanna Dunachie 教授说,辉瑞疫苗两针比一针好,但两针间隔的时间可以根据情况灵活安排 。对于英国目前的情况,她认为8周间隔是最佳时间 。
这类对数据的密切观察分析虽然是在以色列、英国和世界其他国家和地区进行的,但是对别的国家的公共卫生政策有着重要的意义 。例如,是否、什么时候需要打第三针加强针?需不需要恢复社交隔离?等等问题,都可以借鉴这些国家和地区的数据来做决定 。
现有的新冠疫苗是针对还没有这些变异的病毒株研发的 。虽然有研究表明现有的新冠疫苗对某些变异株的效力降低了,但这些疫苗似乎仍能预防感染以后的重症 。确切的结论还需要进一步的研究,疫苗制造商也在开发针对这些变异株的新疫苗 。
参考文献
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