Vaccine-induced neutralizing antibodies (nAbs) are key biomarkers considered to be associated with vaccine efficacy. In United States Government-sponsored phase 3 efficacy trials of COVID-19 vaccines, nAbs are measured by two different validated pseudovirus-based SARS-CoV-2 neutralization assays, with each trial using one of the two assays. Here we describe and compare the nAb titers obtained in the two assays. We observe that one assay consistently yielded higher nAb titers than the other when both assays were performed on the World Health Organization’s anti-SARS-CoV-2 immunoglobulin International Standard, COVID-19 convalescent sera, and mRNA-1273 vaccinee sera. To overcome the challenge this difference in readout poses in comparing/combining data from the two assays, we evaluate three calibration approaches and show that readouts from the two assays can be calibrated to a common scale. These results may aid decision-making based on data from these assays for the evaluation and licensure of new or adapted COVID-19 vaccines.

中文翻译：

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用于 COVID-19 疫苗评估的两种经过验证的 SARS-CoV-2 假病毒中和试验的校准

疫苗诱导的中和抗体 (nAb) 是被认为与疫苗功效相关的关键生物标志物。在美国政府资助的 COVID-19 疫苗的 3 期功效试验中，nAb 是通过两种不同的、经验证的基于假病毒的 SARS-CoV-2 中和试验来测量的，每次试验都使用两种试验中的一种。在这里，我们描述并比较了在两种检测中获得的 nAb 滴度。我们观察到，当对世界卫生组织的抗 SARS-CoV-2 免疫球蛋白国际标准、COVID-19 恢复期血清和 mRNA-1273 疫苗血清进行两种测定时，一种测定始终产生比另一种测定更高的 nAb 滴度。为了克服这种读数差异在比较/组合来自两种测定的数据时所带来的挑战，我们评估了三种校准方法，并表明可以将两种测定的读数校准到一个共同的尺度。这些结果可能有助于基于这些分析的数据做出决策，以评估和许可新的或适应的 COVID-19 疫苗。