Medical College of Wisconsin, Milwaukee, WI, United States.
Division of Hematology/Oncology, Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, United States.
Asian Pac J Cancer Prev. 2024 Feb 1;25(2):393-399. doi: 10.31557/APJCP.2024.25.2.393.
Recipients of allogeneic hematopoietic cell transplantation (alloHCT) are at increased risk of morbidity and mortality due to COVID-19. Immune responses to SARS-CoV-2 vaccines are blunted in these profoundly immunocompromised patients. As a result, novel strategies for protection, such as additional vaccine doses (boosters), are being explored. However, data regarding the efficacy of a third dose of SARS-CoV-2 vaccine in alloHCT recipients are limited and conflicting.
In this systematic review and meta-analysis, we investigated the efficacy of a third dose of SARS-CoV-2 vaccine in alloHCT recipients. The review was conducted following PRISMA guidelines, and 7 studies with 385 alloHCT recipients who received 3 vaccine doses were included. The primary outcomes assessed were the rate of seroconversion following the third dose of vaccine and the rate of seroconversion in patients who did not respond to the initial 2-dose vaccination series.
The pooled humoral response rate after 3 doses of SARS-CoV-2 vaccine in alloHCT recipients was 74%. In a subgroup analysis of patients who did not respond to the initial 2-dose series, the seroconversion rate following the third vaccine dose was 49%. Notably, male patients and those with a shorter interval between alloHCT and the first vaccine dose were more likely to not respond to the third dose.
In conclusion, the pooled humoral response rate of 74% following three doses of SARS-CoV-2 vaccine in alloHCT recipients highlights the potential for protection in this immunosuppressed population. Additionally, encouraging responses in nearly half of the patients who did not seroconvert with the initial 2-dose series suggest the continued utilization of additional vaccine doses until results from large prospective studies become available. These findings are critical for informing vaccination strategies in alloHCT recipients to mitigate the high mortality risk associated with COVID-19.
接受异基因造血细胞移植（alloHCT）的患者因 COVID-19 而面临更高的发病率和死亡率。这些严重免疫功能低下的患者对 SARS-CoV-2 疫苗的免疫反应减弱。因此，正在探索保护的新策略，例如接种额外的疫苗剂量（加强针）。然而，关于 alloHCT 受者接种第三剂 SARS-CoV-2 疫苗的疗效的数据有限且存在争议。
在这项系统评价和荟萃分析中，我们研究了 alloHCT 受者接种第三剂 SARS-CoV-2 疫苗的疗效。本综述按照 PRISMA 指南进行，共纳入了 7 项研究，涉及 385 名接受 3 剂疫苗的 alloHCT 受者。评估的主要结局包括第三剂疫苗接种后的血清转化率和初始 2 剂接种系列未应答患者的血清转化率。
alloHCT 受者接种 3 剂 SARS-CoV-2 疫苗后的总体体液免疫反应率为 74%。在未应答初始 2 剂系列的患者亚组分析中，第三剂疫苗接种后的血清转化率为 49%。值得注意的是，男性患者和 alloHCT 与第一剂疫苗之间间隔较短的患者更有可能对第三剂疫苗无反应。
总之，alloHCT 受者接种 3 剂 SARS-CoV-2 疫苗后的总体体液免疫反应率为 74%，这表明在免疫抑制人群中具有保护作用。此外，初始 2 剂系列未发生血清转化的近一半患者中出现令人鼓舞的反应，表明在获得大型前瞻性研究结果之前，继续使用额外的疫苗剂量。这些发现对于指导 alloHCT 受者的疫苗接种策略至关重要，以降低与 COVID-19 相关的高死亡率风险。
