BACKGROUND This study aimed at evaluation and comparison of PastoCovac Plus protein-subunit vaccine in parallel with ChAdOx1-S (AstraZeneca) and BBIBP-CorV (Sinopharm) in primarily vaccinated volunteers with two doses of ChAdOx1-S or BBIBP-CorV. MATERIALS AND METHODS 194 volunteers enrolled the study who were previously primed with 2 doses of ChAdOx1-S or BBIBP-CorV vaccines. They were divided into two heterologous regimens receiving a third dose of PastoCovac Plus, and two parallel homologous groups receiving the third dose of BBIBP-CorV or ChAdOx1-S. Serum samples were obtained just before and 4 weeks after booster dose. Anti-spike IgG and neutralizing antibodies were quantified and the conventional live-virus neutralization titer, (cVNT50) assay was done against Omicron BA.5 variant. Moreover, the adverse events data were recorded after receiving booster doses. RESULTS ChAdOx1-S/PastoCovac Plus group reached 73.0 units increase in anti-Spike IgG rise compared to the ChAdOx1-S/ ChAdOx1-S (P: 0.016). No significant difference was observed between the two groups regarding neutralizing antibody rise (P: 0.256), indicating equivalency of both booster types. Adjusting for baseline titers, the BBIBP-CorV/PastoCovac Plus group showed 135.2 units increase (P<0.0001) in anti-Spike IgG, and 3.1 (P: 0.008) unit increase in mean rise of neutralizing antibodies compared to the homologous group. Adjustment for COVID-19 history, age, underlying diseases, and baseline antibody titers increased the odds of anti-Spike IgG fourfold rise both in the ChAdOx1-S (OR: 1.9; P: 0.199) and BBIBP CorV (OR: 37.3; P< 0.0001) heterologous groups compared to their corresponding homologous arms. The odds of neutralizing antibody fourfold rise, after adjustment for the same variables, was 2.4 (P: 0.610) for the ChAdOx1-S heterologous group and 5.4 (P: 0.286) for the BBIBP CorV heterologous groups compared to their corresponding homologous groups. All the booster types had the potency to neutralize BA.5 variant with no significant difference. The highest rate of adverse event incidence was recorded for ChAdOx1-S homologous group. CONCLUSIONS PastoCovac Plus booster application in primed individuals with BBIBP-CorV or ChAdOx1-S successfully increased specific antibodies' levels without any serious adverse events. This vaccine could be administrated in the heterologous regimen to effectively boost humoral immune responses.

中文翻译：

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在 ChAdOx1-S 或 BBIBP-CorV 引发的个体中使用 PastoCovac Plus 针对 COVID-19 进行异源加强免疫的免疫原性和安全性。

背景本研究旨在在初次接种两剂 ChAdOx1-S 或 BBIBP-CorV 的志愿者中评估和比较 PastoCovac Plus 蛋白亚单位疫苗与 ChAdOx1-S（阿斯利康）和 BBIBP-CorV（国药集团）的平行情况。材料和方法 194 名志愿者参加了这项研究，他们之前接种了 2 剂 ChAdOx1-S 或 BBIBP-CorV 疫苗。他们被分为接受第三剂PastoCovac Plus的两个异源方案，以及接受第三剂BBIBP-CorV或ChAdOx1-S的两个平行同源组。在加强剂量之前和之后 4 周采集血清样本。对抗刺突 IgG 和中和抗体进行了定量，并针对 Omicron BA.5 变体进行了常规活病毒中和滴度 (cVNT50) 测定。此外，在接受加强剂量后记录不良事件数据。结果 与 ChAdOx1-S/ ChAdOx1-S 组相比，ChAdOx1-S/PastoCovac Plus 组的抗 Spike IgG 升高增加了 73.0 个单位（P：0.016）。两组之间在中和抗体升高方面没有观察到显着差异（P：0.256），表明两种增强剂类型相同。调整基线滴度后，与同源组相比，BBIBP-CorV/PastoCovac Plus 组的抗 Spike IgG 增加了 135.2 个单位（P<0.0001），中和抗体平均增加了 3.1 个单位（P：0.008）。对 COVID-19 病史、年龄、基础疾病和基线抗体滴度进行调整后，ChAdOx1-S（OR：1.9；P：0.199）和 BBIBP CorV（OR：37.3；P）中抗 Spike IgG 的几率增加四倍。 < 0.0001) 异源组与其相应的同源臂相比。调整相同变量后，与相应的同源组相比，ChAdOx1-S 异源组的中和抗体增加四倍的几率为 2.4（P：0.610），BBIBP CorV 异源组的中和抗体增加四倍的几率为 5.4（P：0.286）。所有增强剂类型均具有中和 BA.5 变体的效力，且无显着差异。ChAdOx1-S 同源组的不良事件发生率最高。结论 在携带 BBIBP-CorV 或 ChAdOx1-S 的已免疫个体中应用 PastoCovac Plus 加强剂，成功提高了特异性抗体的水平，且没有任何严重的不良事件。这种疫苗可以在异源方案中施用，以有效增强体液免疫反应。