Search

As severe acute respiratory coronavirus 2 (SARS-CoV-2) variants continue to emerge, it is important to characterize immune responses against variants which can inform on protection efficacies following booster vaccination. In this study, neutralizing breadth and antigen-specific CD8+ T cell responses were analyzed in both infection-naïve and infection-experienced individuals following administration of a booster bivalent Wuhan-Hu-1+BA.4/5 Comirnaty® mRNA vaccine. Significantly higher neutralizing titers were found after this vaccination compared to the pre-third booster vaccination time point. Further, neutralizing breadth to omicron variants, including BA.1, BA.2, BA.5, BQ.1 and XBB.1, was found to be boosted following bivalent vaccination. SARS-CoV-2-specific CD8+ T cells were identified, but with no evidence that frequencies were increased following booster vaccinations. Spike protein-specific CD8+ T cells were the only responses detected after vaccination and non-spike-specific CD8+ T cells were only detected after infection. Both spikespecific and non-spike-specificCD8+ T cells were found at much lower frequencies than CD8+ T cells specific to cytomegalovirus (CMV), Epstein-Barr virus (EBV) and influenza (Flu). Taken together, these results show that the bivalent Wuhan-Hu-1 +BA.4/5 Comirnaty® mRNA vaccine boosted the breadth of neutralization to newer SARS-CoV-2 variants and that vaccination is able to induce spike protein-specific CD8+ T cell responses, which are maintained longitudinally. [ABSTRACT FROM AUTHOR]

As severe acute respiratory coronavirus 2 (SARS-CoV-2) variants continue to emerge, it is important to characterize immune responses against variants which can inform on protection efficacies following booster vaccination. In this study, neutralizing breadth and antigen-specific CD8 + T cell responses were analyzed in both infection-naïve and infection-experienced individuals following administration of a booster bivalent Wuhan-Hu-1+BA.4/5 Comirnaty ® mRNA vaccine. Significantly higher neutralizing titers were found after this vaccination compared to the pre-third booster vaccination time point. Further, neutralizing breadth to omicron variants, including BA.1, BA.2, BA.5, BQ.1 and XBB.1, was found to be boosted following bivalent vaccination. SARS-CoV-2-specific CD8 + T cells were identified, but with no evidence that frequencies were increased following booster vaccinations. Spike protein-specific CD8 + T cells were the only responses detected after vaccination and non-spike-specific CD8 + T cells were only detected after infection. Both spike-specific and non-spike-specific CD8 + T cells were found at much lower frequencies than CD8 + T cells specific to cytomegalovirus (CMV), Epstein-Barr virus (EBV) and influenza (Flu). Taken together, these results show that the bivalent Wuhan-Hu-1+BA.4/5 Comirnaty ® mRNA vaccine boosted the breadth of neutralization to newer SARS-CoV-2 variants and that vaccination is able to induce spike protein-specific CD8 + T cell responses, which are maintained longitudinally., Competing Interests: Authors KJ, DI, and LB are employed by the company Immudex ApS. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Underwood, Sølund, Jacobsen, Binderup, Fernandez-Antunez, Mikkelsen, Inekci, Villadsen, Castruita, Pinholt, Fahnøe, Ramirez, Brix, Weis and Bukh.)