Laboratory medicine, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea.
Division of Infectious diseases, Department of Internal Medicine, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea.
J Infect Public Health. 2023 Oct;16(10):1537-1543. doi: 10.1016/j.jiph.2023.07.017. Epub 2023 Jul 26.
The ongoing COVID-19 pandemic has seen the emergence of numerous novel variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. In this study, we compared the efficacy of three different forms of immunization against the wild-type, delta, and omicron variants of the virus: two doses of the BNT or AZ vaccine (BNT/BNT or AZ/AZ) as homologous vaccination, three doses of AZ/AZ/BNT as heterologous vaccination, and naturally occurring immunization in severe COVID-19 cases.
We collected serum samples from vaccine recipients (67 receiving BNT/BNT, 111 receiving AZ/AZ, and 18 receiving AZ/AZ/BNT) and 46 patients who were admitted to the hospital with severe COVID-19. Blood samples were taken one month after the last injection and the efficacy of the vaccination was determined using the surrogate virus neutralization test (sVNT), with a positive result defined as an inhibition rate of over 30%. Serum samples from COVID-19 patients were taken at various points during their hospitalization and tested for inhibition rates.
Our results indicated that there was no notable difference in the levels of neutralizing antibodies (nAb) in vaccine recipients and patients against the wild-type and delta variants. However, when it came to the omicron variant, the vaccine recipients had significantly lower nAb titers. Among the vaccine recipients, those who received a booster dose of BNT after their first two doses of AZ (AZ/AZ/BNT) demonstrated the highest level of protection against the omicron variant at 44.4%, followed closely by the COVID-19 patients. In analyzing the serial samples taken from hospitalized COVID-19 patients, we observed that their inhibition rates against the wild-type and delta variants improved over time, while the inhibition rate against the omicron variant decreased.
In conclusion, our findings suggest that heterologous booster vaccination after primary vaccination produces higher nAb titers and provides a higher level of protection against the omicron variant compared to primary vaccination alone. This protective effect was similar to that observed in patients with severe COVID-19.
目前正在流行的 COVID-19 疫情出现了许多新型严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）病毒变体。在这项研究中，我们比较了三种不同形式的免疫接种对病毒野生型、德尔塔和奥密克戎变体的疗效：两剂 BNT 或 AZ 疫苗（BNT/BNT 或 AZ/AZ）作为同源疫苗接种，三剂 AZ/AZ/BNT 作为异源疫苗接种，以及严重 COVID-19 病例中的自然感染。
我们收集了疫苗接种者（67 人接受 BNT/BNT，111 人接受 AZ/AZ，18 人接受 AZ/AZ/BNT）和 46 名因严重 COVID-19 住院的患者的血清样本。在最后一次注射后一个月采集血样，并使用替代病毒中和试验（sVNT）测定疫苗接种的效果，阳性结果定义为抑制率超过 30%。在住院期间的不同时间点采集 COVID-19 患者的血清样本，并检测抑制率。
我们的结果表明，疫苗接种者和患者对野生型和德尔塔变体的中和抗体（nAb）水平没有明显差异。然而，当涉及到奥密克戎变体时，疫苗接种者的 nAb 滴度显著降低。在疫苗接种者中，那些在接受两剂 AZ 后接受 BNT 加强剂的人（AZ/AZ/BNT）对奥密克戎变体的保护率最高，为 44.4%，其次是 COVID-19 患者。在分析从住院 COVID-19 患者中采集的系列样本时，我们观察到他们对野生型和德尔塔变体的抑制率随着时间的推移而提高，而对奥密克戎变体的抑制率则降低。
总之，我们的研究结果表明，与单独初级疫苗接种相比，初级疫苗接种后进行异源加强接种可产生更高的 nAb 滴度，并提供更高水平的对奥密克戎变体的保护。这种保护作用与严重 COVID-19 患者相似。
