Abstract：
OBJECTIVE: The emergence of new SARS-CoV-2 variants has led to the development of Omicron-targeting bivalent mRNA vaccines. It is crucial to understand how bivalent vaccines may improve antibody responses against new variants.
METHODS: A total of 107 participants, who had three COVID-19 WT mRNA vaccine doses, were recruited, and given either a monovalent (WT) or a bivalent mRNA vaccination (Pfizer/BioNTech Bivalent (WT and BA.4/BA.5) or Moderna Bivalent (WT and BA.1). Blood samples were taken before booster and at 28 days post-booster.
RESULTS: We found significantly lower fold change in serum binding IgA responses against BA.1, BA.5 and EG.5.1 spike in the bivalent booster group, compared with the monovalent (WT) booster group, following vaccination. However, this was only observed in individuals with prior infection. The relative fold change in serum binding IgA response was more skewed towards WT over variant (BA.1, BA.5 or EG.5.1) spike in previously infected bivalent-booster-vaccinees, as compared with previously infected monovalent-(WT)-booster-vaccinees.
CONCLUSIONS: The findings suggest imprinting of antibody responses that is shaped by the first vaccination (WT spike). Previous infection also affects the boosting effect of follow-up vaccination. Studies are needed to understand how to induce a robust and long-lasting IgA immunity for protection against COVID-19 infection.
METHODS: A total of 107 participants, who had three COVID-19 WT mRNA vaccine doses, were recruited, and given either a monovalent (WT) or a bivalent mRNA vaccination (Pfizer/BioNTech Bivalent (WT and BA.4/BA.5) or Moderna Bivalent (WT and BA.1). Blood samples were taken before booster and at 28 days post-booster.
RESULTS: We found significantly lower fold change in serum binding IgA responses against BA.1, BA.5 and EG.5.1 spike in the bivalent booster group, compared with the monovalent (WT) booster group, following vaccination. However, this was only observed in individuals with prior infection. The relative fold change in serum binding IgA response was more skewed towards WT over variant (BA.1, BA.5 or EG.5.1) spike in previously infected bivalent-booster-vaccinees, as compared with previously infected monovalent-(WT)-booster-vaccinees.
CONCLUSIONS: The findings suggest imprinting of antibody responses that is shaped by the first vaccination (WT spike). Previous infection also affects the boosting effect of follow-up vaccination. Studies are needed to understand how to induce a robust and long-lasting IgA immunity for protection against COVID-19 infection.
摘要：
目的：新的SARS-CoV-2变体的出现导致了Omicron靶向二价mRNA疫苗的开发。了解二价疫苗如何改善针对新变体的抗体反应至关重要。
方法：总共107名参与者，谁有三个COVID-19WTmRNA疫苗剂量，被招募，并且给予单价(WT)或二价mRNA疫苗接种(Pfizer/BioNTech二价(WT和BA4/BA.5)或Moderna二价(WT和BA.1))。在加强之前和加强后28天采集血样。
结果：我们发现，在二价加强组中，血清结合IgA对BA.1，BA.5和EG.5.1峰值的反应倍数变化显着降低，与单价（WT）加强组相比，接种疫苗后。然而,这仅在有既往感染的个体中观察到.在先前感染的二价加强疫苗接种者中，血清结合IgA反应的相对倍数变化更偏向WT变异体（BA.1，BA.5或EG.5.1）峰值，与以前感染的单价（WT）加强疫苗相比。
结论：研究结果表明，抗体反应的印记是由第一次接种（WT尖峰）形成的。以前的感染也会影响后续疫苗接种的促进作用。需要进行研究，以了解如何诱导强大而持久的IgA免疫，以防止COVID-19感染。
方法：总共107名参与者，谁有三个COVID-19WTmRNA疫苗剂量，被招募，并且给予单价(WT)或二价mRNA疫苗接种(Pfizer/BioNTech二价(WT和BA4/BA.5)或Moderna二价(WT和BA.1))。在加强之前和加强后28天采集血样。
结果：我们发现，在二价加强组中，血清结合IgA对BA.1，BA.5和EG.5.1峰值的反应倍数变化显着降低，与单价（WT）加强组相比，接种疫苗后。然而,这仅在有既往感染的个体中观察到.在先前感染的二价加强疫苗接种者中，血清结合IgA反应的相对倍数变化更偏向WT变异体（BA.1，BA.5或EG.5.1）峰值，与以前感染的单价（WT）加强疫苗相比。
结论：研究结果表明，抗体反应的印记是由第一次接种（WT尖峰）形成的。以前的感染也会影响后续疫苗接种的促进作用。需要进行研究，以了解如何诱导强大而持久的IgA免疫，以防止COVID-19感染。
