Khong Ka-Wa, Liu Danlei, Leung Ka-Yi, Lu Lu, Lam Hoi-Yan, Chen Linlei, Chan Pui-Chun, Lam Ho-Ming, Xie Xiaochun, Zhang Ruiqi, Fan Yujing, To Kelvin Kai-Wang, Chen Honglin, Yuen Kwok-Yung, Chan Kwok-Hung, Hung Ivan Fan-Ngai
Department of Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China.
Department of Microbiology, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China.
Vaccines (Basel). 2022 Jan 21;10(2):160. doi: 10.3390/vaccines10020160.
By vaccinating SARS-CoV-2 naïve individuals who have already received two doses of COVID-19 vaccines, we aimed to investigate whether a heterologous prime-boost strategy, using vaccines of different platforms as the booster dose, can enhance the immune response against SARS-CoV-2 virus variants. Participants were assigned into four groups, each receiving different combination of vaccinations: two doses of BNT162b2 followed by one dose of BNT162b2 booster (B-B-B); Combination of BNT162b2 (first dose) and CoronaVac (second dose) followed by one dose of BNT162b2 booster (B-C-B); two doses of CoronaVac followed by one dose of CoronaVac booster (C-C-C); two doses of CoronaVac followed by one dose of BNT162b2 booster (C-C-B). The neutralizing antibody in sera against the virus was determined with live virus microneutralization assay (vMN). The B-B-B group and C-C-B group demonstrated significantly higher immunogenicity against SARS-CoV-2 Wild type (WT), Beta variant (BV) and Delta variant (DV). In addition, the B-B-B group and C-C-B group showed reduced but existing protection against Omicron variant (OV). Moreover, A persistent rise in vMN titre against OV was observed 3 days after booster dose. Regarding safety, a heterologous prime-boost vaccine strategy is well tolerated. In this study, it was demonstrated that using vaccines of different platforms as booster dose can enhance protection against SARS-CoV-2 variants, offering potent neutralizing activity against wild-type virus (WT), Beta variant (BV), Delta variant (DV) and some protection against the Omicron variant (OV). In addition, a booster mRNA vaccine results in a more potent immune response than inactivated vaccine regardless of which platform was used for prime doses.
通过对已接种两剂新冠疫苗的未感染过严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的个体进行疫苗接种，我们旨在研究使用不同平台的疫苗作为加强剂量的异源初免-加强策略是否能增强针对SARS-CoV-2病毒变体的免疫反应。参与者被分为四组，每组接受不同的疫苗接种组合：两剂BNT162b2，随后一剂BNT162b2加强针（B-B-B）；BNT162b2（第一剂）和科兴新冠疫苗（第二剂）组合，随后一剂BNT162b2加强针（B-C-B）；两剂科兴新冠疫苗，随后一剂科兴新冠疫苗加强针（C-C-C）；两剂科兴新冠疫苗，随后一剂BNT162b2加强针（C-C-B）。采用活病毒微量中和试验（vMN）测定血清中针对该病毒的中和抗体。B-B-B组和C-C-B组对SARS-CoV-2野生型（WT）、贝塔变体（BV）和德尔塔变体（DV）表现出显著更高的免疫原性。此外B-B-B组和C-C-B组对奥密克戎变体（OV）的保护作用虽有所降低但仍然存在。此外，加强剂量接种3天后观察到针对OV的vMN滴度持续上升。在安全性方面，异源初免-加强疫苗策略耐受性良好。在本研究中，证明了使用不同平台的疫苗作为加强剂量可以增强针对SARS-CoV-2变体的保护作用，对野生型病毒（WT）、贝塔变体（BV）、德尔塔变体（DV）具有强大的中和活性，并对奥密克戎变体（OV）提供一定的保护。此外，无论初免剂量使用何种平台疫苗，加强接种mRNA疫苗均比灭活疫苗产生更强大的免疫反应。
