背景:SARS-CoV-2加强疫苗接种应理想地增强针对变体的保护并最小化免疫印迹。这项I期试验评估了两种针对SARS-CoV-2β变体受体结合域(RBD)的疫苗:重组二聚体RBD-人IgG1Fc融合蛋白,和编码膜锚定RBD的mRNA。
方法:76名18-64岁的健康成年人,以前接种了许可的SARS-CoV-2疫苗,随机接受第4剂佐剂(MF59®,CSLSeqirus)蛋白疫苗(5、15或45μg,N=32),mRNA疫苗(10、20或50μg,N=32),或安慰剂(盐水,N=12)第三次加强疫苗接种或SARS-CoV-2感染后至少90天。出血发生在第1天(疫苗接种前),8、29
结果:govNCT05272605。
结果:未发生疫苗相关的严重或医疗护理不良事件。蛋白质疫苗反应原性温和,而mRNA疫苗在较高剂量水平下具有中等反应性。最佳抗RBD抗体应答是由较高剂量的每种疫苗引起的。在活病毒中和和替代中也看到了类似的模式,和假病毒中和试验。针对BA.5和最近的omicron亚变体(XBB,XBB.1.5和BQ.1.1)。两种疫苗的结合抗体滴度与许可的二价mRNA疫苗相当。两种疫苗都增强了CD4+和CD8+T细胞活化。
结论:没有安全性问题,反应原性特征温和,与许可的SARS-CoV-2疫苗相似。两种疫苗都显示出对β的强烈免疫增强作用,祖先和omicron菌株。
背景:澳大利亚政府医学研究未来基金,和慈善机构马云基金会和IFM投资者。
BACKGROUND: SARS-CoV-2 booster vaccination should ideally enhance protection against variants and minimise immune imprinting. This Phase I trial evaluated two vaccines targeting SARS-CoV-2 beta-variant receptor-binding domain (RBD): a recombinant dimeric RBD-human IgG1 Fc-fusion protein, and an mRNA encoding a membrane-anchored RBD.
METHODS: 76 healthy adults aged 18-64 y, previously triple vaccinated with licensed SARS-CoV-2 vaccines, were randomised to receive a 4th dose of either an adjuvanted (MF59®, CSL Seqirus) protein vaccine (5, 15 or 45 μg, N = 32), mRNA vaccine (10, 20, or 50 μg, N = 32), or placebo (saline, N = 12) at least 90 days after a 3rd boost vaccination or SARS-CoV-2 infection. Bleeds occurred on days 1 (prior to vaccination), 8, and 29.
RESULTS: govNCT05272605.
RESULTS: No vaccine-related serious or medically-attended adverse events occurred. The protein vaccine reactogenicity was mild, whereas the mRNA vaccine was moderately reactogenic at higher dose levels. Best anti-RBD antibody responses resulted from the higher doses of each vaccine. A similar pattern was seen with live virus neutralisation and surrogate, and pseudovirus neutralisation assays. Breadth of immune response was demonstrated against BA.5 and more recent omicron subvariants (XBB, XBB.1.5 and BQ.1.1). Binding antibody titres for both vaccines were comparable to those of a licensed bivalent mRNA vaccine. Both vaccines enhanced CD4+ and CD8+ T cell activation.
CONCLUSIONS: There were no safety concerns and the reactogenicity profile was mild and similar to licensed SARS-CoV-2 vaccines. Both vaccines showed strong immune boosting against beta, ancestral and omicron strains.
BACKGROUND: Australian Government Medical Research Future Fund, and philanthropies Jack Ma Foundation and IFM investors.