Vaccines Show Potential Recall Responses to Future SARS-CoV-2 Infection

Aug, 2021 - By WMR

A team of researchers from the University of California revealed that vaccines developed by Moderna and Pfizer-BioNTech against COVID-19 generate a coordinated adaptive immune response.

The COVID-19 pandemic has posed a threat to the healthcare industry since its outbreak in late December 2019. Researchers and scientists across the globe have put on efforts to develop therapeutics against SARS-CoV-2. Their intense research and development efforts have resulted in to the emergency use authorization and mass roll-out of various effective vaccines against SARS-CoV-2. The U.S. FDA has approved Pfizer-BioNTech’s BNT162b2 and Moderna’s mRNA-1273 vaccines for emergency use to combat the spread of COVID-19. The results from clinical trials revealed that within one to two months after the second dose of either vaccine show 95% protection against severe acute respiratory syndrome coronavirus 2 and its circulating variants of concern. The researchers in this study explained that these vaccines generated a coordinated adaptive immune response which have the potential to induce responses to future infection with SARS-CoV-2. They found that vaccination activated CD4 T cells and generate robust antigen-specific polyfunctional CD4 T cell responses. They also observed clonally expanded CD8 T cells in all vaccine recipients. In this study, the researchers used single-cell RNA sequencing and functional assays to evaluate antibody and cellular responses to two doses of either of the vaccines. They observed that the neutralizing antibodies were detected within two weeks after receiving the first dose of vaccine and the levels increased manifold after second dose.

The findings of the study shed light on expansion of plasmablast and increase in spike-specific B cells after two weeks of receiving second dose of either of the vaccines which indicates the establishment of long time memory and potential recall responses to infection.