背景:需要了解SARS-CoV-2突破性感染如何影响针对现有和应急前SARS-CoV-2菌株的免疫反应的广度,以制定基于证据的长期免疫策略。
方法:我们进行了随机,从2021年10月开始,在100名接种BNT162b2的未接种感染的个体中评估同源(BNT162b2)与异源(mRNA-1273)加强疫苗接种的免疫原性。进行事后分析以评估SARS-CoV-2感染对针对野生型SARS-CoV-2和/或Omicron亚变体的体液和细胞免疫应答的影响。
结果:93名参与者在第360天完成了研究。71%(66/93)的参与者在研究结束时报告了首次SARS-CoV-2Omicron感染,同源和异源加强组之间的感染比例相似(72.3%[34/47]vs69.6%[32/46];p=0.82)。在第180天,异源加强组的平均野生型SARS-CoV-2抗S-RBD抗体水平明显高于同源组(14,588IU/mL;95%CI,10,186-20,893vs7447IU/mL;4646-11,912;p=0.025)。与未感染的参与者相比,在OmicronBA.1/2波期间经历突破性感染的参与者针对野生型SARS-CoV-2的抗S-RBD抗体水平以及针对BA.1和应急前BA.5的抗体中和水平明显更高。不管杂种免疫状态如何,野生型SARS-CoV-2抗S-RBD抗体水平在加强后或SARS-CoV-2感染后六个月后显着下降。
结论:与BNT162b2相比,用mRNA-1273加强疫苗接种与显著更高的抗体水平相关。未感染患者的抗体反应范围更窄,下降更快,接种疫苗的个人。如果在感染爆发前不久和最后一次感染或加强后至少六个月施用,则加强剂可能更有效。
背景:新加坡NMRC,USFDA,MRC。
BACKGROUND: Understanding how SARS-CoV-2 breakthrough infections impacts the breadth of immune responses against existing and pre-emergent SARS-CoV-2 strains is needed to develop an evidence-based long-term immunisation strategy.
METHODS: We performed a randomised, controlled trial to assess the immunogenicity of homologous (BNT162b2) versus heterologous (mRNA-1273) booster vaccination in 100 BNT162b2-vaccinated infection-naïve individuals enrolled from October 2021. Post hoc analysis was performed to assess the impact of SARS-CoV-2 infection on humoral and cellular immune responses against wild-type SARS-CoV-2 and/or Omicron subvariants.
RESULTS: 93 participants completed the study at day 360. 71% (66/93) of participants reported first SARS-CoV-2 Omicron infection by the end of the study with similar proportions of infections between homologous and heterologous booster groups (72.3% [34/47] vs 69.6% [32/46]; p = 0.82). Mean wildtype SARS-CoV-2 anti-S-RBD antibody level was significantly higher in heterologous booster group compared with homologous group at day 180 (14,588 IU/mL; 95% CI, 10,186-20,893 vs 7447 IU/mL; 4646-11,912; p = 0.025). Participants who experienced breakthrough infections during the Omicron BA.1/2 wave had significantly higher anti-S-RBD antibody levels against wildtype SARS-CoV-2 and antibody neutralisation against BA.1 and pre-emergent BA.5 compared with infection-naïve participants. Regardless of hybrid immunity status, wildtype SARS-CoV-2 anti-S-RBD antibody level declined significantly after six months post-booster or post-SARS-CoV-2 infection.
CONCLUSIONS: Booster vaccination with mRNA-1273 was associated with significantly higher antibody levels compared with BNT162b2. Antibody responses are narrower and decline faster among uninfected, vaccinated individuals. Boosters may be more effective if administered shortly before infection outbreaks and at least six months after last infection or booster.
BACKGROUND: Singapore NMRC, USFDA, MRC.