Heterologous priming with the ChAdOx1 nCoV-19 vector vaccine followed by boosting with a messenger RNA vaccine (BNT162b2 or mRNA-1273) is currently recommended in Germany, although data on immunogenicity and reactogenicity are not available. In this observational study we show that, in healthy adult individuals (n = 96), the heterologous vaccine regimen induced spike-specific IgG, neutralizing antibodies and spike-specific CD4 T cells, the levels of which which were significantly higher than after homologous vector vaccine boost (n = 55) and higher or comparable in magnitude to homologous mRNA vaccine regimens (n = 62). Moreover, spike-specific CD8 T cell levels after heterologous vaccination were significantly higher than after both homologous regimens. Spike-specific T cells were predominantly polyfunctional with largely overlapping cytokine-producing phenotypes in all three regimens. Recipients of both the homologous vector regimen and the heterologous vector/mRNA combination reported greater reactogenicity following the priming vector vaccination, whereas heterologous boosting was well tolerated and comparable to homologous mRNA boosting. Taken together, heterologous vector/mRNA boosting induces strong humoral and cellular immune responses with acceptable reactogenicity profiles.

德国目前建议使用 ChAdOx1 nCoV-19 载体疫苗进行异源引发，然后使用信使 RNA 疫苗（BNT162b2 或 mRNA-1273）加强免疫，尽管没有关于免疫原性和反应原性的数据。在这项观察性研究中，我们表明，在健康成人 ( n  = 96) 中，异源疫苗方案诱导了尖峰特异性 IgG、中和抗体和尖峰特异性 CD4 T 细胞，其水平显着高于同源载体后疫苗加强 ( n  = 55) 和更高或在量级上与同源 mRNA 疫苗方案相当 ( n = 62)。此外，异源疫苗接种后的尖峰特异性 CD8 T 细胞水平显着高于两种同源方案后。刺突特异性 T 细胞主要是多功能的，在所有三种方案中产生大量重叠的细胞因子表型。同源载体方案和异源载体/mRNA 组合的接受者报告了在引发载体疫苗接种后更大的反应原性，而异源加强耐受性良好并且与同源 mRNA 加强相当。总之，异源载体/mRNA 加强诱导具有可接受的反应原性特征的强体液和细胞免疫反应。